their last job (on account of Lennie's awkward encounter with a woman), they are alone once again. They do have each other but they are consistently running from job to job because this was the nature of itinerant ranch hands at that time, and because Lennie always got into some trouble; he and George had left previous jobs prematurely because of this. 

George criticizes Lennie constantly but only to keep him out of trouble. George knows that without Lennie, he would have an easier time staying at a job, rather than being repeatedly cast out from jobs/society because of Lennie's innocent but dangerous social awkwardness: 

"God, you're a lot of trouble," said George. "I could get along so easy and so nice if I didn't have you on my tail. I could live so easily and maybe have a girl." 

But, since George has taken the responsibility of looking after Lennie, he must retreat from society with Lennie, whenever Lennie gets into some trouble or has trouble fitting in. The first chapter ends with another desolate and lonely description: a coyote (wild) howling up the river and a dog (tame/society) answering from the other side. At this point, George and Lennie are more like the coyote, away from society (in the wild). 

In Section/Chapter 2, George and Lennie are introduced to those that work on the ranch. Toward the end of this section, Lennie decides that the place is too "mean" and he tries to convince George that they should leave. George agrees that he doesn't like it there but tells Lennie they should wait and try to make some money. They both know that, because of Lennie, it is difficult for them to fit in. By not fitting in, Lennie must feel a sense of loneliness. The only reason he doesn't feel completely alone, even in the company of others, is because he has George with him. 

The section ends with Candy's ancient dog laboring over to the door. The dog, being old and obsolete, also doesn't fit in. The dog is somewhat of a parallel to Lennie. The only difference is that Lennie can still perform a function (physical work) while the dog has no useful purpose other than companionship for Candy. After everyone has left for dinner, the dog is left alone: 

After a moment the ancient dog walked lamely in through the open door. He gazed about with mild, half-blind eyes. He sniffed, and then lay down and put his head between his paws. 

In the next chapter, Candy, like his dog, is also getting old and feels like he might be obsolete and lonely as well. Foreseeing the day when his dog will die and when the ranch might have no more use for him, Candy will ask George and Lennie if he can join them when they leave to start their own farm. Both Candy and Lennie (and George, although he really doesn't voice it much) fear being alone. 

Working backwards, chapter 3 ends with the idea of Lennie feeling loneliness if he is denied the opportunity to tend the rabbits.  Despite the fact that he broke Curley's hand and that he has instigated the elements that will lead to his demise, Lennie feels a sense of loneliness if he is not able to tend the rabbits.  It is for this reason he pleads with George so that he is not inevitably feeling alone and apart from his true love.

Curley experiences loneliness in how everyone else in the bunkhouse has seen him effectively beaten by Lennie.  There is a loneliness that he displays, even though he is amongst everyone else.  His claim to fame was that he could "lick anyone."  Lennie effectively disproved that and, in the process, Curley feels extremely alone as a result.  As George talks to Slim, he explains the reason he befriended Lennie was to escape his own sense of loneliness as a migrant worker:

I ain’t got no people. . . . I seen the guys that go around on the ranches alone. That ain’t no good. They don’t have no fun. After a long time they get mean. They get wantin’ to fight all the time.

While Lennie might be a nuisance to George, he is the reason that George is able to escape his condition of loneliness.  Certainly, Candy feels alone now that his dog has been shot.  Candy feels this sense of loneliness in the "silence" that Steinbeck continually raises in the chapter.  Candy's dog experiences his own loneliness in those fateful last moments before Carlson's luger silenced him for good.  The result is that Candy's loneliness compels him to latch on to the dream that Lennie and George share, reflecting a discomfort with his condition of loneliness.

Because of the setting, the characterization of Crooks is meant to demonstrate the effects of racism and discrimination. He is physically isolated and lonely—he is not allowed into the bunkhouse with the other ranch hands. Curley's wife realizes the delicate position Crooks is in, and she uses his race against him, indicating that one accusation from her "could get [him] strung up on a tree so easy it ain't even funny." Crooks is intentionally isolated at the ranch and in society at large, and this creates a deep loneliness within him.

Because of the threats Candy's wife makes, Crooks is frightened into solitude. If he can't trust her, then he feels he shouldn't trust anyone else on the ranch, either. He tells Candy,

Maybe you guys better go. ... I ain't sure I want you in here no more. A colored man got to have some rights even if he don't like 'em.

Crooks doesn't like being so isolated, yet he also believes that there is safety in removing himself from the presence of white people. He turns to isolation and therefore loneliness as a means of protecting himself, but notes that he doesn't like it.

Crooks seems to find Lennie the least threatening ranch hand. When Lennie approaches him privately, it doesn't take Crooks long to warm up to the idea of friendly conversation:

Crooks scowled, but Lennie's disarming smile defeated him. "Come on in and set a while," Crooks said. "'Long as you won't get out and leave me alone, you might as well set down." His tone was a little more friendly. "All the boys gone into town, huh?"

Crooks typically tosses everyone out of his room, establishing clear physical boundaries. Yet Lennie's efforts to befriend him feel genuine, and Crooks softens to the possibility of engaging with someone else on the ranch.

In his conversation with Lennie, Crooks shares bittersweet memories of his childhood:

"The white kids come to play at our place, an' sometimes I went to play with them, and some of them was pretty nice. My ol' man didn't like that. I never knew till long later why he didn't like that. But I know now."

He hesitated, and when he spoke again his voice was softer. "There wasn't another colored family for miles around. And now there ain't a colored man on this ranch an' there's jus' one family in Soledad." He laughed. "If I say something, why it's just a nigger sayin' it."

Themes of loneliness have been woven into Crooks's entire life. As a child, he didn't know another Black family and played with white children, much to his father's dismay. His need for childhood friendship was great, and his sense of innocence prevented him from realizing the inherent dangers in such relationships. Now as an adult, he faces much the same situation, isolated because of his race. In these reflections, the pain of a lifetime of isolation and loneliness weighs heavily on Crooks.

Steinbeck - Of Mice and Men

Chapter 4 is the "Crooks chapter." His bunk is in the harness room, separated (segregated) from the others who sleep in the bunkhouse. Crooks is ostracized because he is black. He is even excluded from playing cards. Lennie asks why he isn't wanted. Crooks says: 

’Cause I’m black. They play cards in there, but I can’t play because I’m black. They say I stink. Well, I tell you, you all of you stink to me. 

Crooks is very protective of his space and his room. He thinks that if the others don't want him in their space, they have no right in his. As a result, he is isolated and out of spite, embraces that isolation. 

At the end of this chapter, Curley's wife comes into Crooks's room. Candy and Lennie are there as well. This completes the group of isolated misfits. Crooks is racially isolated. Candy is (like his dog) isolated to a smaller degree because he is old and not very useful as a worker. Lennie has been an outcast throughout his life, that is, until George took him under his wing. Curley's wife is the only woman on this ranch and is starved for attention and companionship. When Crooks suggests that she leave, she replies that she is lonely as well. She manages to insult all three of them while simultaneously claiming that she's grateful to have them to talk to: 

Ever’body out doin’ som’pin’. Ever’body! An’ what am I doin’? Standin’ here talkin’ to a bunch of bindle stiffs—a nigger an’ a dum-dum and a lousy ol’ sheep—an’ likin’ it because they ain’t nobody else.” 

Almost all of the characters deal with loneliness and isolation to some degree in Steinbeck's novella. The two characters who could be considered the loneliest, however, are Crooks and Curley's wife. For a brief time Candy is also quite lonely.

Crooks is the black stable buck on the ranch. He is also partly crippled after being kicked by a horse. Because he's a black man on a ranch dominated by white men he is the victim of both racism and segregation. He is usually not allowed in the white bunkhouse and the one time he is welcome he is involved in a fight, presumably over race. Candy describes the scene:

"They let the nigger come in that night. Little skinner name of Smitty took after the nigger. Done pretty good, too. The guys wouldn’t let him use his feet, so the nigger got him. If he coulda used his feet, Smitty says he woulda killed the nigger. The guys said on account of the nigger’s got a crooked back, Smitty can’t use his feet.” 

Crooks, Lennie, and Candy each suffer from situations that still cause discrimination today: race, mental disability, and age. In addition, Crooks and Candy both have physical handicaps.

Crooks is black and so is shunned by the other ranch hands, who won't share the bunk house with him. They tell him he "stinks," and he is forced to sleep in trough of straw off the harness room of the barn. (He has made the room his own, showing his intelligence with his books.) He spends a good deal of time alone because the other men don't much want to be associated him, and he has learned to accept being lonely. Curley's wife intimidates and humiliates him with the threat of a lynching. Crooks also has a bad back (the source of his nickname) from an injury, which doesn't help him to be accepted.

Lennie is mentally disabled. Since he often doesn't understand what is going on, it is difficult for him to be included in the other men's activities. In addition, George shelters him and tries to keep him apart from the others so that no trouble starts. His being alone is a danger too, as the story shows.

Candy is aging and missing a hand. His chief companion is his old dog, but Carlson shoots the dog because it is blind, smells bad, and is a nuisance in the bunk house. Candy fears he will be fired and left alone to die when he gets too old to work.

Today we have more understanding and compassion for people in the situation of these three men, and legal protections are in place that at least attempt to safeguard people from discrimination.

The characters of Candy, Lennie, and Crooks are all considered outcasts, in one way or another, in Steinbeck's novel Of Mice and Men.

First, Candy is considered an outcast given that he has simply outworn his ability to function as a worker on the farm. This is mirrored by the fact that his dog is put down for being too old. Candy can be seen in the same way which the dog is: useless and beyond help. The other ranchers' insistence that the dog needs to be put down, based upon his uselessness. Candy recognizes the fact that, one day, he will be seen as useless and discarded as well. Therefore, he is considered an outcast given his uselessness (though the men do not admit it yet--it is coming).

Lennie is an outcast given his diminished mental capacity. His presence on the ranch would not be allowed if George was not there to look out for him and insure that he did what was expected. The fact that he is an outcast is also seen when the men go after him (after he murders Curley's wife) instead of protecting him (as they would if he were a true member of the ranchers' family).

Lastly, Crooks is seen as an outcast for two reasons. First, Crooks is black. Therefore, he is not regarded as having the same worth as a white worker. Second, Crooks has been injured. His ability to perform the duties expected of him have been reduced. Given that he had dedicated his life to the ranch is the only reason he has been allowed to stay.

I do think they are both symbols of loneliness in one simple way: they are each a representative of an under-represented social class.

Curley's wife is the only woman in the entire novel who has a speaking part. Look at her name! She doesn't even receive an identity of her own. I think this shows that she represents an independent or individual or isolated experience.

Crooks, likewise, is the only black man on the ranch. He has to deal with being separated from the rest of the men because he smells different. He even physically has a different sleeping location. He too is isolated, representing loneliness. 

Are you sure that there is supposed to be anything beyond the simple fact that they are really lonely and act really lonely?  I do not really think they are supposed to symbolize anything -- at least not in the way that the farm that Lennie and George dream of symbolizes freedom or Candy's dog represents what happens to people who outlive their usefulness.

To me, Curley's wife and Crooks just ARE lonely, as you say.  They show how loneliness affects people -- Crooks tries to destroy Lennie's dream even though he really wants to share in it, Curley's wife acts in ways that will get the men in trouble even though she really wants their company.  But I do not see them as symbols.  I see them more as characters who are defined by their loneliness.

There is not enough evidence in the story that would substantiate that Slim is a lonely man. This is, if you use the word "lonely" to the same extent as it is applied to Curley's Wife, Candy, and Crooks. If you compare the four, Slim would definitely stick out as the one who is the least lonely of them all. In fact, Slim seems to have achieved a level of self-sufficiency which may be the result of a life which, in his eyes, is somewhat satisfactory.

To answer this question with more accuracy, I would bounce back to the two main characters, and focus mostly on George, and not Lennie. Why? Because Lennie, in his mind of a simpleton, knows and trusts that George will always be his companion. He makes plans that include George, feels safe with him, and has developed a bond that is strong enough for him to know that George is not going anywhere.

Yet, what about George's own needs? He does not see Lennie under the same light as Lennie sees him. George is basically dragging around life with Lennie because he is compassionate enough to help him. However, he lives in consistent anxiety and stress hoping and praying that Lennie's rough ways will not cause another accident, or another accidental death-which is worse. He worries about what Lennie says and does all the time. He knows that Lennie is a burden, but it is one that George sees himself carrying for the rest of his life. This is not exactly what he envisions for himself as a person, but it is what he has come to accept.

Therefore, George is the loneliest of them all. He does not fit in with the ranch hands as well as the others fit in with each other, he has to live with the burden that is Lennie, and he has to look out for himself because he has nobody else.

In the end, when Lennie accidentally kills Curley's wife, George did the ultimate act of mercy by shooting Lennie in order to spare him a slow death in the hands of a vengeful lynch mob. When Lennie dies, we can feel deeply how lonely George truly is in this world, and we can also realize how lonely he has always been.

Loneliness is an important theme in Of Mice and Men. However, Crooks is more severely affected than most of the characters. Cut off by color segregation from the gregarious atmosphere of the ranch house, he lives alone in the harness room. He is "more permanent than the other men," and his loneliness is exacerbated by constantly seeing ranch hands come and go. This is one reason why he is so cynical about George and Lennie's dream of buying their own land, as he has seen many former hands fail to accomplish this. Nonetheless, his loneliness is such that, even though he does not believe they will achieve their dream, he offers to come and work for them free of charge if they ever do.

Crooks hesitates to make this suggestion, and it is clearly difficult for him to unbend in this way. It is clear from Steinbeck's description of Crooks that his loneliness is perpetuated by a vicious circle. He is described as "a proud, aloof man" who "kept his distance and demanded that other people keep theirs." When he discovers George and Lennie in his room, he peremptorily orders them to get out, saying:

"I ain't wanted in the bunkhouse, and you ain't wanted in my room."

"Why ain't you wanted?" Lennie asked.

"'Cause I'm black. They play cards in there, but I can't play because I'm black. They say I stink. Well, I tell you, you all of you stink to me."

Years of segregation and harsh treatment have exacerbated Crooks's bitterness and, consequently, his loneliness. He is now hostile to the men who sleep in the bunkhouse, even on the rare occasions when they want to be friends with him. He is envious of George and Lennie's friendship, as well as the camaraderie of the bunkhouse, complaining to Lennie:

You got George. You know he's goin' to come back. S'pose you didn't have nobody. S'pose you couldn't go into the bunkhouse and play rummy 'cause you was black. How'd you like that?...A guy goes nuts if he ain't got nobody.

Curley's wife is so lonely on the ranch because she is new there, is the only female, and doesn't get along well with Curley.

We learn early on from from Candy that Curley and his wife have only been married for "two weeks." She hasn't had a chance to settle in and make a life for herself. Being the only woman on the ranch isolates her. She says to Crooks, who wants her to stay of his room,

Think I don't like to talk to somebody ever' once in a while? Think I like to stick in that house alla time?

She goes on to explain that the self-absorbed Curley only wants to talk about himself. She gets tired of hearing his bragging blow-by-blows about fights he has gotten into:

Think I'm gonna stay in that two-by-four house and listen how Curley's gonna lead with his left twice, and then bring in the of right cross?

Curley's wife is a teenage girl who would like to be truly seen by someone for the person she is. Her husband understands her as a trophy wife or prop to support him. She dresses brightly and provocatively to attract the attention she so badly needs. She wants to not feel invisible, and yet her dress and makeup earn her the label of a "tart" by the men of the ranch. They try to avoid her so as to avoid trouble, which further isolates her.

Curley's wife herself is shallow from having had a narrow life. She tries to reach out, but she is so young she lacks the wisdom to know how to do it effectively.

Curley can be seen as lonely because he is unable to emotionally connect with anyone on the ranch.

Curley brings much of his isolation on himself.  He is threatened by "big guys" and demonstrates physical aggression often, channeling his previous occupation as a boxer. The ranch hands know this, as seen in how Candy describes Curley as always wanting to "pick on big guys."  Curley is also alone because of his status as the boss's son.  No ranch hand really wants to get to know Curley because they know that it might impact their job on the ranch.  Curley accepts the social estrangement associated with being the boss's son and does not seek to overcome this for the purpose of forging emotional connection with the drifting farm hands who make up his social world.

Curley is also lonely because of his relationship with his wife. He and his wife are not emotionally connected to one another.  As Whit says, Curley's wife spends her time looking for Curley, who, in turn, spends his time looking for her.  Neither one is able to find emotional comfort within the other. The result of this emotional separation is a feeling of loneliness within Curley.  There is a difference between being alone and being lonely.  The former indicates some level of contentment.  Curley is not really alone, but he's lonely because he is unable to find a sustainable emotional connection. 

The pain of loneliness is one of the major themes in Steinbeck's novella. The characters who are overtly lonely include Crooks and Curley's wife, but an argument could be made that all the characters suffer from loneliness and alienation. Lennie and George have a distinct advantage over the other characters because they have each other. Lennie is often saying, in reference to their friendship and how others might be alone:

“But not us! An’ why? Because . . . . because I got you to look after me, and you got me to look after you, and that’s why.”

As the son of the boss, Curley is alienated from the bindle stiffs, who avoid engaging with him out of fear for their jobs because the jealous Curley always suspects the men of flirting with his wife.

After Curley belligerently enters the bunkhouse, George warns Lennie that because of the way Curley has acted and how he has looked at Lennie, Lennie will have trouble with Curley and they will be fired. 

"Look, Lennie. You try to keep away from him, will you? Don't never speak to him. If he comes in here you move clear to the other side of the room. Will you do that, Lennie?"

Apparently, Curley is very high strung and possessive of his new wife. Of course, there is some justification for this anxiety over what his wife is doing or where she might be since there are no other women on the ranch and she is pretty and rather seductive in her actions. But, because he is always so suspicious of the other men, Curley cannot be friends with anyone. His tone of voice is always threatening to them, and he seems to be looking for a fight.
In Chapter 3, Curley steps into the bunkhouse and looks

...threateningly around the room. "Where the hell's Slim?"
"Went out into the barn," said George. "He was gonna put some tar on a split hoof."
Curley's shoulders dropped and squared. "How long ago'd he go?"
"Five-ten minutes."
Curley jumped out the door and banged it after him.

One of the workers named Whit says that he is going to watch what happens.

"Curley's just spoilin' or he wouldn't start for Slim....I like to see the fuss if it come off."

Later, Slim comes into the bunkhouse, his hands black with tar. Curley follows and apologizes to Slim, "Well, I didn't mean nothing, Slim. I just ast you."
Slim says,

"Well, you been askin' me too often. I'm gettin'...damn sick of it. If you can't look after your own...damn wife, what you expect me to do about it? You lay offa me."

Curley tries to apologize, but Carlson then injects his opinions, saying Curley should tell his wife to stay home. Letting her "hang around bunk houses" will soon bring trouble, he warns. Enraged that a mere ranch hand would talk this way to him, Curley tells Carlson to stay out of his conversation with Slim, or he can step outside with him if he wants. Carlson laughs and accuses Curley of being afraid of Slim. Moreover, he threatens Curley if he tries anything with him.

Clearly, Curley's quick temper is a problem for him. He seems to be always looking for a fight to prove that he is superior, perhaps because he is insecure about his marriage. At any rate, he finds himself without any friends because he is so suspicious of the men, suspecting that they are interested in his new wife.

Loneliness is a major theme in Of Mice and Men, so the topic itself is fine for a thesis, but remember a thesis is supposed to make a claim or argument, so consider carefully what you want to say about it.

Here are some examples of loneliness along with some ideas to get you started on the actual thesis statement:

1)  Lennie and George have no real home, being migrant workers.  They work the season, then move on, so they have no family, no community, not ties except each other.

2)  Candy is a senior citizen with a physical handicap, and even though we get the sense he has been at the ranch for some time, he has few ties or friends either, and tells Lennie and George later in the story that he has no family, no kids.  He is alone in most senses of the word.

3)  Curley's Wife is in an unhappy marriage, and more or less trapped on the farm.  She seeks the male company of many of the workers simply for someone to talk to, and since Curley himself is such an abusive jerk.

As for a thesis, consider how just about every character is lonely in some way, and how this was common during the Great Depression the story takes place in.  You can argue that Steinbeck reinforces the frightening, lonely and troubled times of the Depression by reinforcing the loneliness of the characters.  Also try to think of another argument of your own to include in a thesis based on these or other examples.  Post again if you want a critique of your final thesis.

Because Crooks is black, the unspoken norms of segregation isolate him. He sleeps in his own room, described as a "little shed" that leans against the barn. At first glance, he seems like little more than an animal. His bed is a "long box filled with straw" and he lives with his medicine bottles mingled on a shelf with the medications for the horses. However, we learn he has magazines, a dictionary, a copy of the California civil code and a few "dirty books" on his shelf, so we can conclude that he is an intelligent man and that one way he deals with his loneliness is through reading.

Crooks has put up a huge number of defenses against getting hurt. He tells Lennie that he's not allowed to sleep in the bunkhouse because he's black, and he can't play cards with the other men because they say he "stinks." His chief coping mechanism is to stay aloof from the others. He says they "stink." But it doesn't take him long to open up to Lennie when he realizes that Lennie won't harm him:

You got George. You know he’s goin’ to come back. S’pose you didn’t have nobody. S’pose you couldn’t go into the bunk house and play rummy ‘cause you was black. How’d you like that? S’pose you had to sit out here an’ read books. Sure you could play horseshoes till it got dark, but then you got to read books. Books ain’t no good. A guy needs somebody—to be near him.” He whined, “A guy goes nuts if he ain’t got nobody. Don’t make no difference who the guy is, long’s he’s with you. I tell ya,” he cried, “I tell ya a guy gets too lonely an’ he gets sick.”

We see here that Crooks' loneliness is eating him alive. He says a little later that it is making him crazy. For a moment, he is even so taken by the idea of George and Lennie's farm and the society it could offer that he offers to go in with them on it. Then reality intrudes and the defenses kick in: he says he doesn't want it after all and it will come to nothing. Crooks' chief method of coping with loneliness and the other pain he carries is to try to crush any illusion he has that things will get better.

The black "stable buck," Crooks, who is marginalized from the society of the other men because he is not allowed to sleep in the bunkhouse as they do, spends lonely nights in the barn, where he has fashioned a room of his own near the stalls for the mules. Unlike some of the other bindle stiffs, Crooks is able to read, and he spends many hours in this occupation. Because of the back injury which has awarded him the nickname he has, Crooks spends much time applying liniment to his pained back that was once broken. In addition, Crooks is fastidious, sweeping his meager quarters and straightening things. Even though it is a Saturday night, Crooks "kept his distance and demanded that others keep theirs." In his meager room, a small electric bulb casts a meager light and Crooks reads from one of his books or magazines.

Candy is lonely because he is devoid of any real human contact.  He is kept as a cleaner on the ranch on the account of losing his hand in a machinery accident.  He does not have any real human connection with anyone on the ranch, as most ranch-hands are more focused on their own job, making their bit, and not on him.  Candy's only real companion is an old sheep dog.  Like Candy, the dog is well past his prime, but used to be useful.  The dog and Candy are the only companions for one another.  His being on the ranch as one without promise or possibility for advancement only accentuates Candy's lonely condition.  

When Carlson puts down Candy's dog, Candy's loneliness magnifies.  It is out of this that he chances into the plans of George and Lennie and financially commits himself.  Upon seeing Curley's wife's dead body, it becomes clear that his dreams are gone and his loneliness is underscored even more.  Candy's loneliness is present because he lives in a world without dreams or hope and without companionship to help make life worth living.

Whether Candy is the loneliest man in the narrative of John Steinbeck is debatable as many interpret Crooks as the character who is separated from others and is the most alienated. However, because Candy is handicapped and old, and he loses his beloved dog, he certainly feels very much alone.

Here are some reasons that Candy is very lonely:

• Candy is marginalized as he remains behind when all the other men go out into the fields to work.
• He fears saying anything that might anger others. When he returns to the bunkhouse after the boss talks with George and Lennie in Chapter 2, for example, Candy is quick to say that he was not listening in on the conversation:

"I didn't hear nothing you guys was sayin'. I ain't interested in nothing you was sayin". A guy on a ranch don't never listen nor he don't ast no questions."

• In his loneliness, he tries to ingratiate himself to Lennie and George, telling them the boss is "a nice fella...You got to take him right."
• Candy tries to be friendly and inform the newly hired George and Lennie about others.  For instance, after Curley leaves, Candy explains that Curley is the boss's son and he does not care what he says or does. "Seems like Curley is cockier'n ever since he got married," he adds.
• When he "draws a derogatory statement from George," Candy feels reassured and opens up with George and Lennie, hoping to have someone with whom to talk.
• When Carlson complains of his old dog, Candy "looked for help from face to face," and he "looked for a long time at Slim to try to find some reversal."  But, when Slim tells him that the dog should be put down, Candy acquiesces and puts his arm over his face. When he hears the gun shot, Candy rolls over on his bed and turns to the wall in his grief and aloneness.
• After overhearing George and Lennie speak of their dream farm, Candy cannot help asking them, "S'pose I went in with you guys....I could cook and tend the chickens and hoe the garden some. How'd that be?" He also informs them that he has $250.00 from his accident.  The idea of living on a farm with others entrances Candy because he is alone and worried about his future.
• After discovering that Curley's wife is dead, Candy expresses "his greatest fear. 'You an me can get that little place, can't we, George?'" Then he drops his head as he knows the dream, too, has died. He "looked helplessly back at Curley's wife" as his terrible aloneness returns.

Here is how Candy has coped with his loneliness:

• After George and Lennie let Candy in on their dream of owning a piece of land, Candy is much happier, for now he has a purpose to live and the hope for a comfortable future.  This dream gives Candy something to ward off his loneliness; it also provides him a reason to live, for he feels he will not be lonely with George and Lennie.
• Whenever he sees Curley's wife, he hopes she will go away because she is troubling.
• He asks to be included in George and Lennie's plan to have a farm of their own.
• Thinking of the farm and calculating about it gives Curley hope; he rushes into the barn and tells Lennie in front of Crooks, "I got it figured out. We can make some money on them rabbits if we go about it right...."
• When Crooks mocks his optimism, Candy retorts," ...we gonna do it now, and don't make no mistake about that....That money's in the bank...."

Loneliness is a major theme in Of Mice and Men. George is talking with Lennie about loneliness in chapter one:

Guys like us, that work on ranches, are the loneliest guys in the world. They got no family. They don’t belong no place. . . . With us it ain’t like that. We got a future. We got somebody to talk to that gives a damn about us. We don’t have to sit in no bar room blowin’ in our jack jus’ because we got no place else to go. If them other guys gets in jail they can rot for all anybody gives a damn. But not us.

George is talking about how fortunate he and Lennie are to have each other. It is a lonely life for guys like George and Lennie. They have no other family members. They move from ranch to ranch. They meet other ranch hands who are very lonely.

Crooks is lonely. He is isolated from everyone else because he is black:

Crooks, the despairing old Negro stable worker, lives alone in the harness room, ostracized from the ranch hands.

On the one occasion when Crooks talks with Candy and Lennie, he is negative and tells them they will never attain their dream of owning their own place:

Crooks tells them they will never attain their dream. Crooks is excluded from the rest of the ranch hands.

Candy is lonely. He invites himself to be a part of George's and Lennie's dream of becoming a home owner. He feels lesser than the other ranch hands because of his injury. He finds much joy in dreaming right along with George and Lennie about one day buying a home:

Candy is the old, disabled ranch hand who is helpless to stop the shooting of his dog and who knows that he too will be banished when he is no longer useful. He is sweetly hopeful of joining Lennie and George on their dream farm, offering to contribute his savings of $350 to buy the farm.

No doubt, the novel is filled with lonely characters. Curley's wife is perhaps the loneliest of them all. She has no other female companions. She is surrounded by men. She reaches out to someone like Lennie due to her loneliness:

But she is pathetically lonely and had once had dreams of being a movie star. Both she and Crooks crave company and "someone to talk to."

Lennie is lonely too. He reaches out to Curley's wife. He accidentally breaks her neck and George realizes the dream is over:

On Sunday afternoon, while the others are playing horseshoes, Curley's wife gets Lennie to feel her soft hair. When he begins to muss it, she panics, and he accidentally breaks her neck. When George discovers what has happened, he realizes that their dream is over.

Truly, the characters in Of Mice and Men live a lonely existence. Even having each other does not fill the void at times.

While it's difficult to say who the loneliest character in the novel is, there are two prime candidates: Curley's wife and Crooks.

In order to show why these two are better candidates for loneliest than the others on the ranch, it's important to look at how Curley's wife and Crooks are different than the others. The most obvious way in which these two are different is the fact that they are not white males. Curley's wife is the only woman in the novel, and Crooks, "the negro stable buck," is the only black man in the novel. The others are all able to have at least a little bit of company. Crooks says the major difference between him and the other men perfectly in Chapter 3 of the novel: "They play cards in [the bunkhouse], but I can't play because I'm black. They say I stink."

As the only woman in the book, Curley's wife suffers a similar type of loneliness that Crooks suffers from. While she is married to Curley, the boss's son, she seems to have no relationship with the man. Near the end of the novel, she tells Lennie she doesn't like being around her husband because "He ain't a nice fella."  She is always looking for him while he is always looking for her. There is not one part of the novel when the two are seen together. She deals with her loneliness in looking for comfort from the other men. She goes into the bunkhouse and into Crooks's stable to flirt. The men call her a "tart," but "lonely" seems to be a more appropriate term for her in these instances.

While each of the white men in the novel suffer from a type of loneliness, they all have each other. Even George seems to find friendship with Slim in the few pages that occur after he shoots Lennie. 

Even though the extent to which Crooks and Curley's wife experience loneliness is abundant, I would probably argue that Curley's wife is the loneliest character. While Crooks is not allowed in the bunkhouse with the white men, he is allowed to mingle with them outside. He is needed on the ranch. Curley's wife, however, is not needed. Curley goes to whores instead of going to his wife and the other men on the ranch are afraid to talk to her. Instead, the only person on the ranch who is willing to be around her turns out to be the same person who kills her.

There are no direct quotes that clearly state that Candy is lonely, rather you have to infer his loneliness from what he says and does. For example when he overhears George telling Lennie about the dream of owning a patch of land, he is eager to jump in and join them in this dream, offering his own money to help them purchase some land:

"Tell you what -" He leanded forward eagerly. "S'pose I went in with you guys. Tha's three hundred an' fifty bucks I'd put in. I ain't much good, but I could cook and tend the chickens and hoe the garden some. How'd that be?"

He is even willing to leave his money to George and Lennie if he dies. We can see here his desperation for companionship and fellowship because of his loneliness.

Likewise we can infer his loneliness by his reluctance to let his dog be shot. He tries again and again to put of Carlson from shooting his dog, and he reveals the friendship he has had with him:

"Well - hell! I had him so long. Had him since he was a pup. I herded sheep with him."

His reluctance to let his dog be killed and the way he keeps on trying to change the subject and put Carlson off clearly indicates how important this dog is to Candy - he only friend.

In John Steinbeck’s novel Of Mice and Men, Candy is a sad, lonely figure whose most important companion in life is an old, sickly dog that the other men in bunkhouse would rather was dead because of its awful stench. The dog clearly means everything to Candy, and the constant complaints about the dog’s smell invariably meet with the same reply, such as occurs in the following exchange, in which Carlson has just entered the bunkhouse after spending time outside playing horseshoes:

"Damn right he is," said Carlson. "He don't give nobody else a chance to win-" He stopped and sniffed the air, and still sniffing, looked down at the old dog. "God awmighty, that dog stinks. Get him outa here, Candy! I don't know nothing that stinks as bad as an old dog. You gotta get him out."

Candy rolled to the edge of his bunk. He reached over and patted the ancient dog, and he apologized, "I been around him so much I never notice how he stinks." 

The importance of the dog to Candy is evident right up until he finally succumbs to his coworkers’ complaints and allows them to shoot the dog. The emotional trauma associated with the imminent loss of his closest companion is noticeable in Candy’s being reduced to a near-catatonic state in which he seeks to shut out the world to insulate him from his pain.  The following passage illuminates the old crippled man’s emotional pain at the loss of his beloved pet:

Slim said, "Candy, you can have any one of them pups you want."

Candy did not answer. The silence fell on the room again. It came out of the night and invaded the room.

The door opened and Lennie and Carlson came in together. Lennie crept to his bunk and sat down, trying not to attract attention. Carlson reached under his bunk and brought out his bag. He didn't look at old Candy, who still faced the wall.

That the dog represented the only family Candy had is made further evident in the passage during which George is discussing his and Lennie’s plans for a place of their own, where they’re the boss.  Candy, anxious to join this hypothetical endeavor, appeals to George for a place at the table: 

“. . .I could cook and tend the chickens and hoe the garden some. How'd that be?"

George half-closed his eyes. "I gotta think about that. We was always gonna do it by ourselves."

Candy interrupted him, "I'd make a will an' leave my share to you guys in case I kick off, 'cause I ain't got no relatives nor nothing.”

Steinbeck makes clear that Candy is alone in the world, and that the old dog was all he had to call his own.  In a story full of sadness and despair, Candy stands out as a lonely, solitary figure.

Candy is isolated and alienated for various reasons. He's old and he's missing a hand. His age might be overlooked if he still had the use of both hands; however, the missing hand causes Candy to be less useful than he once was. In this sense, Candy is alienated because he's not as useful as other ranch workers. Candy is also isolated because he doesn't have any family around him. He has other workers, but that's not the same as having a loving and supportive family. Chapter 3 gives readers a good quote about his alienation. We see that Candy is so much on his own and by himself that he doesn't even have any relatives to will his money to.

George half-closed his eyes. "I gotta think about that. We was always gonna do it by ourselves." Candy interrupted him, "I'd make a will an' leave my share to you guys in case I kick off, 'cause I ain't got no relatives or nothing . . . "

To make the lack of family even worse, Candy no longer has the company of his dog:

"I shouldn't ought to of let no stranger shoot my dog."

Prejudice is a theme present in the book, and prejudice seeks to alienate people from each other for one reason or another. Take Crooks for example. He's alienated because of his skin color, but that kind of racism and prejudice works both ways. White people are alienated from black people too. It's not just blacks being alienated from whites. Chapter 4 has a good quote showing how this happened to Candy.

Candy leaned against the wall beside the broken collar while he scratched his wrist stump. "I been here a long time," he said. "An' Crooks been here a long time. This's the first time I ever been in his room."

Crooks said darkly, "Guys don't come into a colored man's room very much."

You may wish to argue that the historical setting of the Great Depression generated first the disenfranchisement of many workers which, in turn, led to loneliness as men had to become itinerant and leave their homes. Then, the fear of others competing against them for the same jobs kept men alienated from one another. And, thirdly, the alienated and lonely lives that men lived in the 1930s resulted in their becoming cruel to one another.

Here, then are some ideas to help you get started (You will want to find supporting details for these points):

1. Disenfranchisement leads to loneliness - In contrast to the other bindle stiffs, George and Lennie travel together, mainly because George has promised Lennie's Aunt Clara that he will care for the mentally challenged man. Theirs is not so much a friendship as a symbiotic relationship: George is the brains and Lennie the brawn. The other ranch workers have no friends as they are strangers to one another. Curley is separated from the others by virtue of being the boss's son, and Slim must remain somewhat aloof as the mule skinner. Crooks, the black stable mate is marginalized by his color. 
2. Fear of others leads to alienation - Old Candy worries that he will be fired when he is no longer useful and able to swamp out the bunkhouse: "Jus' as soon as I can't swamp out no bunk houses they'll put me on the county"; Crooks worries about the racial prejudice of the others: "They play cards in here, but I can't play because I'm black. They say I stink"; and all the workers fear Curley's anger since he is the son of the boss. After he challenges Lennie, George tells Lennie, "Ya know, Lennie, I'm scared I'm gonna tangle with that bastard myself...."
3. This alienation and loneliness leads to cruelty among the men. Curley becomes pugnacious and Whitson wants to shoot the old dog of Candy. When Lennie comes into Crooks's room, the stable mate is cruel to him, telling Lennie that George might not return, ""...s'pose George went into town tonight and you never heard of him no more.....S'pose he gets killed or hurt so he can't come back."

You might not have to offer "arguments" about loneliness in Steinbeck's book. It might be simpler to offer three examples of loneliness. Then if you feel there is a need to argue about anything, you might use that in your conclusion. Personally, I don't see that there is anything to argue about, although there are good examples of loneliness.

The loneliest character in the book is Crooks, whose pitiful situation is described in the opening of Chapter 4. He is forced to live by himself because of racial prejudice. He is further handicapped by being badly crippled. He copes with his loneliness by reading.

In contrast to Crooks, Curley's wife is the next loneliest character. She is white, young, and attractive, but the men are all afraid to have anything to do with her because she is the wife of the boss's son who could get them fired, and also because she is "jail bait," meaning that she is a minor. She is restless and capable of causing trouble because of her loneliness. Her loneliness actually causes her death when she becomes too friendly with the apparently harmless and simple-minded Lennie.

For a third example, I suggest you use the little story George tells Lennie in the first chapter. Although it comes first in the book, it might be most effective if used at the end of your essay. (It's always a good idea to save the best for last.) Here is what George tells Lennie in Chapter 1 while they are sitting by the campfire:

"Guys like us, that work on ranches, are the loneliest guys in the world. They got no family. They don't belong no place. They come to a ranch an' work up a stake and then they go inta town and blow their stake, and the first thing you know they're poundin' their tail on some other ranch. They ain't got nothing to look ahead to."

This is mainly what Steinbeck's book is about. The men who live in the bunkhouse are all loners. They have no loved ones, and their only possessions are the few things they can roll up in a blanket and carry on their backs when they either want to or are forced to move on. They may not even understand that they are lonely. George seems brighter and more philosophical than most of them. It is he who realizes that "Guys like us, that work on ranches, are the loneliest guys in the world."

Steinbeck was a compassionate man. He truly felt sorry for the kinds of underprivileged people he writes about, and he makes the reader share his feelings.

Crooks is one of the weakest characters in the novella and is the only worker who suffers from racial discrimination. Crooks occupies the lowest social caste on the ranch because he is the only black worker on the farm. Crooks cannot even live with the other workers in the bunkhouse and is forced to reside in a small room attached to the barn. Crooks is also physically weak and gets his name from his crooked back. Crooks even occupies a lower social caste than Curley's wife, who threatens to have him hanged in chapter four. One could argue that Crooks is the loneliest, weakest character in the novella because he suffers from racial discrimination and lacks individual freedom.

Candy is also depicted as an extremely weak character in the novella. Candy is the old swamper, who lost one of his hands in a farm accident. Candy understands that he is essentially useless on the farm and realizes that it is only a matter of time before he is let go. Similar to his ancient dog, Candy's old age and physical limitations negatively affect his social status on the ranch. However, Candy hopes that he will be able to contribute to George and Lennie's dream and eventually live on their own estate. Unfortunately, Candy's dream is destroyed when Lennie accidentally kills Curley's wife.

This is tough because often times the "weak" characters portray the most strength in character.

Physically, Lennie is clearly the work horse in the story, but mentally he is much weaker than his counterparts. He is "slow". He is very childlike in the story and often times has to be treated as such. He also does not have a very strong grasp on his emotions. He cannot channel his feelings in a normal way and often times in the story his feelings of anger are expressed with a violence that is more intense than his actual feelings. For example when he killed the puppy or when he killed Curly's wife. Each instance was a true accident because he didn't mean to kill them, but his expression of anger got away from him. This display of his weakness should not downplay his strength of character and his undying loyalty.

Curly's wife could also be another character that is perceived as weak. She is pretty and knows it, but she is also a victim of a loveless marriage to a very insecure man. She is weak in that she lacks affection and seeks it in the wrong places. This weakness was ultimately her demise in the story because she flirts with Lennie, knowing that he was "slow", and Lennie did not know how to handle the sexual feelings she aroused in him. If she had been loved she might have lived, but her need for affection was her ultimate weakness.

Sure…but weak in what sense?
If you mean weak in the sense of not having strong wills/a focused sense of self, I'd say that the weakest characters are Candy, and, curiously, Curley. He's so threatened by his wife that he has to lord it over the other men via his position and threats of violence.

If you mean weak as in badly drawn or characterized, I'd say that Curley's wife is a bit of a stereotype, and that Slim is too pure.
Greg

Each of the characters you mention deals with loneliness, although the reasons for that loneliness vary.  While each of the characters experiences a sense of isolation, the degree to which each man feels separated from others also differs from character to character.

At times, Lennie seems to be at least somewhat cognizant of the fact that he is a less than desirable traveling companion.  Because of this, he feels a sense of isolation that is assuaged only by George's companionship.  When Crooks questions Lennie about what he would do if George did not return from town, Lennie reacts with fear.

"He won't do it," Lennie cried.  "George wouldn't do nothing like that.  I been with George a long time.  He'll come back tonight--" But the doubt was too much for him.  "Don't you think he will?"

Crooks is isolated physically, as well as emotionally, due to his race.  Because he is African-American, Crooks is not allowed to interact with the other men on a truly "free" basis.  He makes this obvious during his conversation with Lennie.

Candy is partially isolated physically, since he can't work with the men in a typical way and must make do with "lesser" work.  He is also isolated emotionally, since he is aware of the implications of his disability and aging.

Isolation plays a definitely role in the the life of Curley's wife, who feels as she has been left out of a great many things and done and injustice in being only "Curley's wife."  She reacts to her seperation with poor behavior and desperation, as well as self-pity.

"...Seems like they ain't none of them cares how I gotta live.  I tell you I ain't used to livin' like this.  I coulda made somethin' of myself...I don' like Curley.  He ain't a nice fella...Coulda been in the movies, an' had nice clothes--all them nice clothes like they wear..."

Despite their great differences, each of the four characters mentioned is alike in his or her separation.  The loneliness resulting from their shortcomings or burdens could have brought them closer to others, but it was allowed to isolate them instead.

In Of Mice and Men, four characters are most disadvantaged. First, Lennie is mentally handicapped. He has the mind of a child. He lives and works in a man's world, but he functions as a child. He is constantly in trouble. He makes immature decisions which create difficulties in his life. Although he works hard, Lennie is weakened by his immaturity:

Lennie is a good worker and has the strength to do much of the farm work. Yet, handicapped by his lack of adult intelligence, Lennie is doomed in the world of the migrant worker.

George is often frustrated with Lennie because of his immature actions. Lennie definitely finds himself disadvantaged.

Candy is at a disadvantage. He lost a hand in his work on a ranch. Now, he cleans up the bunkhouse. He feels threatened as far as his job is concerned:

Candy is the old, disabled ranch hand who is helpless to stop the shooting of his dog and who knows that he too will be banished when he is no longer useful.

Candy realizes that he is not as useful as he once was. He is disadvantaged in his crippled situation.

Crooks is at a disavantage because he is black. He is ostracized by some of the other white ranch hands. He has to sleep in separate quarters:

Crooks, the despairing old Negro stable worker, lives alone in the harness room, ostracized from the ranch hands.

Also, Crooks is not invited to join the others in their pleasurable activites such as playing games. His opinion does not count among the other ranch hands.

Curley's wife finds herself at a disadvantage. She is the only female on the ranch. She lives a lonely existence. Her husband keeps her isolated from others. She has to deal with Curley's possessive nature. She lives a miserable life. She only dreams about the days she could have been an actress. She flirts with the other men due to her loneliness:

Curley's wife (as the boss's son's flirtatious wife, she is not identified by any other name) wanders around the ranch searching for some human contact. She is stereotyped by the men as a "tart." Indeed, she plays the vamp, which enrages her jealous husband. George tells Lennie to avoid her, calling her "poison" and "jailbait." But she is pathetically lonely and had once had dreams of being a movie star.

She lives a life filled with disadvantages.

John Steinbeck’s novella Of Mice and Men evokes many emotions from the characters and the readers.   From the beginning of the story, it is apparent that Lennie and George will have to face something tragic.  Lennie’s retardation, his temper, and his powerful physical strength are a “time bomb.” George knows that Lennie must be protected, but he cannot be with him every minute of the day. 

When Lennie is left to his own devices, he breaks the rules that George has set for him.  His love of petting soft things overwhelms his need to please George.  When Lennie kills the puppy and Curley’s wife, there is no way that George can fix this for him.  George suffers the most when he is forced to kill Lennie.

Curley cannot be reasoned with about this murder because he already hates Lennie.  George assumes that if Curley catches Lennie he will hurt him before he kills him.  If Lennie were placed in the legal system, he would not be able to survive without George.  In George’s mind, there is nothing to do but take care of Lennie himself.  He determines to kill him to prevent him from harming anyone else and receiving a punishment that he would not understand.

Lennie said, “I thought you was mad at me, George.”

“No,” said George. “No, Lennie.  I ain’t mad. I never been mad, an’ I aint’ now. That’s a thing I want ya to know.”

And George raised the gun and steadied it, and he brought the muzzle of it close to the back of Lennie’s head. The hand shook violently, but his face set and his hand steadied.  He pulled the trigger.  Lennie jarred, and then settled slowly forward to the sand…

As a dynamic character, George learns that one should never take advantage of those who cannot help themselves. When George has to protect Lennie, he understands that there are those people who prey on the weak.  George appears to be gruff and insensitive, yet he protects Lennie and wants to get to the farm where life will be better.

George never tells his feelings for Lennie.  It is obvious that he loves him. After he shoots Lennie, George realizes that now he is no different than all of the other miserable men who wander through the world looking for something better. He knows now that all of his talk about finding a farm and a happier life will never happen.  With Lennie gone, George surrenders his hope.

Despite the many troubling situations that George had to endure to save Lennie, George still wanted Lennie to survive.  He will now go through the rest of life with the guilt of Lennie’s death on his conscience. His vision of the farm has been taken with the death of his friend.

To answer this question, let's explore the suffering of some of the characters. As always, with opinion questions, you will want to be sure to back up your opinion with support from the text.

Most of the characters are suffering migrant workers in pursuit of the American Dream. They receive low wages for tough labor, and their living conditions are less than ideal.

Candy is old, "stoop-shouldered," and only has one hand. He worries about his position on the ranch, which is why he wants to join up with Lennie and George. When they arrive, his only friend is his smelly dog that is killed by Carlson. Candy sees George's plan as an escape from his suffering.

Crooks is a black stable hand, and in addition to living with the same suffering of the migrant workers, he additionally suffers from racism. He is isolated from the others. He also has a crooked back from an incident with a horse.

Curley's wife suffers as she feels lonely in her marriage and has no companions on the ranch. She is the only female character and not even named, as the others refer to her as "tramp" and "tart." She seeks human connection but loses her life for it.

Lennie suffers from an intellectual handicap. Although it is never named or defined, it is clear that he relies on George for protection and guidance. While we may pity Lennie, we could also argue that he does not suffer as much as the others. He seems to be happy in his life with George, enjoying their dream but also finding joy in the little things (such as petting small animals). Although he dies in the end, he is mercifully killed with one shot by his best friend while thinking about their dream, so he does not suffer in his death.

George is the one who takes care of Lennie and ultimately kills him, so we might say that George suffers the most. George is simultaneously held back by Lennie; though he also suffers after losing his best friend.

Curley’s wife is alienated because she married a pompous idiot who keeps her on his ranch, lording her beauty over the other men.  She has no friends, and she is completely isolated.

Curley’s wife does not even have a name of her own.  She is a new wife, and the men say that “Curley is cockier'n ever since he got married” (ch 2, p. 13).  She is always objectified, described as a flirt and a “looloo” and she’s got the eye.

She ain't concealin' nothing. I never seen nobody like her. She got the eye goin' all the time on everybody. I bet she even gives the stable buck the eye. I don't know what the hell she wants. (ch 3, p. 25)

George immediately calls her a “tramp” when he first finds out about her, and believes she is trouble.  He tells Lennie to keep away from her.

Curley’s wife is ridiculed and treated as nothing more than a sexual object, but she has dreams.  She tells them that she could have been “in shows” and I guy told her he could put her in movies (ch 4, p. 38).  Instead, she has no one.

"-Sat'iday night.  Ever'body out doin' som'pin'. Ever'body! An' what am I doin'? Standin' here talkin' to a bunch of bindle stiffs… an' likin' it because they ain't nobody else." (ch 4, p. 38)

Curley’s wife calls the men “bindle bums” and gets frustrated because they don’t tell her things.  This only increases her alienation, because on the one hand she feels she is better than them, while on the other hand they won’t treat her like she means anything.

All page numbers from: http://staff.oswego.org/ephaneuf/web/ENG_9R/Steinbeck,%20John%20-%20Of%20Mice%20and%20Men.pdf

In the world of the itinerant worker during the Great Depression in Of Mice and Men, the competition for jobs was sharp as strangers vied against one another for work.  This strained relationship of men resulted in cruelty, aggressiveness, and a certain alienation of one from another.  For those like Candy, the old swamper who has lost a hand in a machine, life is threatening as he worries about being cast out because he may be seen as useless.  Like his dog, he is also old, and this age causes him anxiety as well.

Relagated to cleaning at the ranch where he lost his hand in an accident, Candy greets George and Lennie as they arrive; but, he is very cautious. When George spots the spray to kill lice over his bed, and asks the old man about it, Candy replies with a cryptic, "I don't know."  As George persists, Candy measures his words,  because he does not want them to leave as he may be accused of running them off.  Then, after the boss questions George and Lennie, but Lennie does not speak, he tells George he will be keeping an eye on him.  As Candy appears, George accuses him of eavesdropping, but Candy emphatically denies doing so because he does not want any trouble,

"I didn't hear nothing....  I ain't interested in nothing you way sayin'.  A guy on a ranch don't never listen nor he don't ast no questions."

Of course, Candy merely says this to win the trust of George because he fears for his job, and does not wish to alienate himself.  After Curley enters the bunkhouse and insults Lennie when Lennie does not answer him, George asks Candy what is wrong with Curley.  Again Candy is cautious; he looks at the door to be sure no one is listening before he answers.  Trusting George, Curley confides,

"That the boss's son....Curley's pretty handy.  he done quite a bit in the ring.  he's lightweight, and he's handy....He hates big guys.  he's alla time picking scraps with big guys kind of like he's mad at 'em because he ain't a big guy."

Lonely for companionship, Curley confides even further in George, telling him about Curley's wife, but asking him to keep his words in confidence.  George promises.

Sociable, Candy is, nevertheless, intimidated by others.  In his loneliness, he has only the company of his old dog.  But Carlson, who complains that the dog smells, offers to shoot it with a kruger.  Candy cannot endure the idea of getting rid of his old sheep dog that he has had since he was a pup.  He says "proudly,"

"you wouldn[t think it to look at him now, but he was the best damn sheep dog I ever seen.

Candy looked a long time at Slim to try to find some reversal.  And Slim gave him none.  At last Candy said softly and hopelessly, "Awright--take'im.'  He did not look down at the dog at all....and stared at the ceiling.

Bereft of any companionship and love with the death of his beloved old dog; Candy worries that, he, too, may be cast out.  When George and Lennie befriend him and allow him to contribute to the dream of a ranch of their own, Candy is renewed and feels befriended.  He feels empowered and scolds Curley's wife when she comes around, knowing she threatens the men's friendships. After she is dead, Candy knows that the dream, too, is dead.  He looks "helplessly back at Curley's wife,"

"you --- --- tramp," he said viciously.  "You done it, di'n't you?  I s'pose you're glad.  Ever'body knowed you'd mess things up.  You wasn't no good." 

Steinbeck demonstrates the painful reality of being discriminated against.  

Discrimination is a recurring theme in the work.  In the opening pages, George and Lennie suffer economic discrimination. They are migrant workers.  They lack a stable source of income.  As a result, Steinbeck shows at least one occasion where they experience prejudice or discrimination. The first involves a bus driver and what George perceives as unfair treatment:

We could just as well of rode clear to the ranch if that bastard bus driver knew what he was talkin’ about. ‘Jes’ a little stretch down the highway,’ he says. ‘Jes’ a little stretch.’ God damn near four miles, that’s what it was! Didn’t wanta stop at the ranch gate, that’s what. Too God damn lazy to pull up. Wonder he isn’t too damn good to stop in Soledad at all. Kicks us out and says ‘Jes’ a little stretch down the road.’ I bet it was more than four miles.

George believes that the bus driver believed himself to be "too damn good to stop in Soledad."  George perceives this to be the case because he is poor. The implication is that the bus driver would have driven them to their destination had they been wealthy.  Being poor and limited, the bus driver does not treat George and Lennie as he would a wealthy customer.  This is a form of economic discrimination and its hurt shows in George's tone.

Crooks experiences racial discrimination.  This can be seen from a physical point of view, as Crooks has to live in separate quarters than the other ranch hands.  This is segregation, a form of racial discrimination that prevents Crooks from participating in what the other men experience.  Another example of racial discrimination can be seen in a passing comment he makes to Lennie regarding why he is alone:  

“Why ain’t you wanted?” Lennie asked.

“’Cause I’m black. They play cards in there, but I can’t play because I’m black. They say I stink. Well, I tell you, you all of you stink to me.”

Crooks's statement reflects the hurt that is a result of example of racial discrimination.  Others judge him as someone who "stinks" because of his race.  In both instances, Crooks experiences racial discrimination. 

• Relationship with his wife

The young girl with failed hopes of becoming a movie star that Curley meets when he is at the Riverside Dance Palace in Salinas later confides in Lennie and tells him that she married Curley not long after nearly leaving home with two other men. She simply wanted out of her lonely and desperate life, and hoped by marrying Curley and going with him that she could become an actress somewhere. Now on the ranch, she finds herself as alienated as before, except she has a man living with her who is interested in her only as a sexual possession that he can flaunt. He is infuriated when she comes around the bunkhouse because he does not want anyone to speak to her or be near her, yet he does not seem to spend much time with her either. 

• Relationship with others

As the son of the boss, Curley likes to "throw his weight around," asserting his power over the ranch hands; however, in truth, he has a complex about his size and tries to compensate for it with his belligerent behavior. Oddly, he wears one glove with vaseline in it in order to keep that hand soft for his very young wife; one man ridicules him, saying Curley "has ants in his pants." With his short temper and male frustrations, he is ready to fight the first man who challenges him, as he prides himself upon having been a welterweight boxer.  Of course, most are reluctant to do so, only because they risk being fired by Curley's father. Therefore, Curley is often alienated as much as the bindlestiffs are. Most of the men avoid Curley, or curtly respond to him as they can only incur problems with his jealousy over his wife, the only woman on the ranch, his short-man complex, his need to prove his male superiority, and his quick temper.

• Behavior at the end of the novella

Perceiving the huge, lumbering Lennie as a physical threat and having been humiliated by Lennie's effortless, mighty crushing of his hand, Curley becomes intensely excited about being able to avenge himself for the loss of his pride as well as the loss of his other possession, his wife. He immediately flares up:

Curley came suddenly to life. "I know who done it," he cried. "That big son-of-a-bitch done it. I know he done it....." He worked himself into a fury. "I'm gonna get him. I'm going for my shotgun...." 

When George pleads with Curley not to shoot Lennie, Curley snaps back heartlessly to Lennie's friend,

"Don't shoot 'im?" Curley cried. "He got Carlson's Luger. 'Course we'll shoot 'im."

Truly, Curley is selfish, impetuous, and cruel.

During Lennie's conversation with Crooks, Crooks describes the men on the ranch as lonely, homeless individuals, who live transient lives traveling from ranch to ranch looking for work. Crooks tells Lennie,

"I seen hundreds of men come by on the road an' on the ranches, with their bindles on their back an' that same damn thing in their heads. Hundreds of them. They come, an' they quit an' go on; an' every damn one of 'em's got a little piece of land in his head. An' never a God damn one of 'em ever gets it. Just like heaven. Ever'body wants a little piece of lan'" (Steinbeck, 36).

Even though Slim is depicted as a wise authority figure, he still works on the ranch and does not have a family of his own. Slim does not mention a dream of owning his own homestead, but continually travels into town to congregate with women and drink, which signifies that he is a rather lonely man, like the other workers on the ranch.

Curley is the boss's son, who is portrayed as an aggressive man. When George first arrives on the ranch, Candy tells him, "Well, I think Curley's married... a tart" (Steinbeck, 14). Curley's wife causes him stress, and he is continually looking for her on the ranch. Curley reveals that he is an insecure man who is rather lonely because his wife does not show him affection. She is unhappy with their marriage and continually attempts to talk to the ranch workers. Curley fears that his wife will cheat on him, which is why he is constantly upset and looking for her.

In Steinbeck's use of the Burns's line, one can see how it foreshadows a sense of loneliness that pervades the work.  The standard translation of the line reads as, "The best-laid plans of mice and men / Often go awry."  This reflects a condition of loneliness in how these plans are all that keep humans company.  When they "go awry," the human being is lost, left without anything else to accompany them.  Certainly, this condition is seen in George, when his plans "go awry" and he has to undertake an action that will leave him condemned to loneliness for as long as he lives.  Candy feels this same loneliness when he encounters the body of Curley's wife.  In this instant, he spits venom at the corpse, calling her names out of hurt because he knows that his plans have also gone "awry" at that moment.  The "plans" that Curley's wife had for her life have "gone awry."  This has caused her to be lonely in her life and yearning for company.  For these characters, the plans they made and all the hope and expectation that were put in them have dissipated into nothing more than a cavernous regret and a sense of abandonment.  This is where Steinbeck's use of Burns's line helps to foreshadow the loneliness that is a part of the text and the worl's overall message.

A prevalent theme of Steinbeck's "Of Mice and Men" is the alienation of men, particularly in the Depression era when so many had to abandon their homes and become itinerant workers in efforts to seek employment.  This motif of separation from the bonds of love and fraternity is exemplified in several of the characters, and Curly is one of them.

In contrast to George and Lennie, two friends who move around together, Curly has a partner, a wife, with whom he lives.  However, she is a cheap woman who merely married for some security.  Often she comes by the other men under the pretext of "looking for Curley":

She put her hands behind her back and leaned against the door frame so that her body was thrown forward. 'You're the new fellas that just come, ain't ya' [she says to George]....She turned her head. 'Hi, Slim,' she said.

Slim's voice came through the door. 'Hi, Good-lookin''

Later, when Curly seeks his wife in the bunkhouse, Slim turns angrily upon him,

'Well, you been askin' me too often.  gettin' God damn sick of it.  If you can't look after your own God damn wife, what you expect me to do about it?  You lay offa me.'

Thus, rather than providing Curly with love and companionship, she becomes a source of anxiety to him, causing him to come into conflict with the other men, conflicts he seeks to resolve by confronting Lennie.  But, instead of asserting his dominance, Curly is hurt when, with animal strength, Lennie crushes his hand.

The son of the boss, Curley is not displaced and alienated from society as the other men are.  However, in his personal life, Curley has no friends since he has estranged himself from the men in the bunkhouse because of his jealousy for his wife.  George reflects upon the trouble that women can be by recalling to Lennie that their friend Andy Cushman is in San Quentin prison "on account of a tart."  Because of his "tart" wife, Curley is outside the fraternity of the men, a brotherhood that Steinbeck felt was a necessity to the happiness of men.  For, it is the dream of community and home that Lennie and George that keeps them from feeling so much their terrible aloneness.

Crooks is the black stable buck character in Steinbeck's Of Mice and Men. He takes care of the horses and mules and lives by himself in the barn. Because he is black, he's segregated from the other men on the ranch, who are all white. He is also the victim of racism. The theme of his loneliness revolves around not having another guy around to talk to as well as the prejudice he faces.

He is envious of George and Lennie because they travel around together and have each other as companions, sharing experiences and conversations. Crooks expresses this envy when he's talking to Lennie in his room in the barn in chapter four:

"I seen it over an’ over—a guy talkin' to another guy and it don’t make no difference if he don’t hear or understand. The thing is, they’re talkin’, or they’re settin’ still not talkin’. It don’t make no difference, no difference.” His excitement had increased until he pounded his knee with this hand. “George can tell you screwy things, and it don’t matter. It’s just the talking. It’s just bein’ with another guy. That’s all.” 

John Steinbeck’s Of Mice and Men is a story about the “little guys” in Depression-era America. Almost all of the characters are people trying to survive in an inhospitable world. Many of the challenges the characters face are economic, but some are the result of prejudicial attitudes. Below are three key minor characters from the book, along with examples of how they are discriminated against.

Candy is the old “swamper” who maintains the bunkhouse.  He is missing part of an arm from an old farm-machinery accident:

1. As an older and disabled worker, he is given only menial chores to do, such as sweeping out the bunkhouse.

2. He has an old dog that he loves. However, another character named Carlson can’t stand the smell of the dog and talks Candy into letting him shoot the dog. Carlson does not take Candy’s feelings into account, most likely because he does not deem him to be an important part of the ranch anymore.

3. He knows that because of his age and disability, he will soon be let go by the boss. He tells George and Lennie,

“They’ll can me purty soon. Jus’ as soon as I can’t swamp out no bunkhouses they’ll put me on the county.”

That’s why he wants to join George and Lennie when they plan to buy their own place.

Crooks is the black stable-buck:

1. He is separated from the white workers. Not allowed to live in the bunkhouse, he has a room in the stable with the horses.

2. When the white men play horseshoes and get together on Sunday, he is not welcome to join them.

3. In the key scene in his room, with George, Lenny, and Candy present, Curley’s wife threatens him,

“Well, you keep your place then, nigger. I could get you strung up on a tree so easy it ain’t even funny.”

Curley’s wife is married to the boss’s son. She is unhappily stuck on the ranch with a bunch of men she doesn’t particularly care for, and she feels that she has lost her chance to “be somebody":

1. Her husband Curley wants her to stay put on the ranch and avoid talking to the men, but they are all there is to socialize with. It is cruel to set such limits on a young woman who wants to see the world.

2. Other characters assume that she is going to cause trouble. George says,

“She’s gonna make a mess. They’s gonna be a bad mess about her. She’s a jail bail all set on the trigger.”

3. When she confronts Lennie in the barn about the bruises on his face, the other men refuse to speak to her, making her feel like an outcast.

Curley is isolated from the ranchhands since he is the son of the boss in Steinbeck's Of Mice and Men.  But, this isolation evolves into alienation as Curley, in his separateness from the others, becomes extremely aggressive, challenging the men of the bunkhouse when he enters it.  He is also insecure about his small stature and about his wife, who is no longer content to sit at home.  So, to disguise his feelings of inadequacy, he bursts into the bunkhouse, demanding if any of the workers have seen his wife, looking threateningly about the room.  When he confronts Slim, Curley is rebuffed; the well-respected Slim tells him to "lay offa me."

That Curley is alienated from the others is clearly evident when Carlson and even old Candy join the verbal attack initiated by Slim.  But, when Lennie smiles in enjoyment, Curley spots a potential victim on whom he can unleash his bitter feelings of alienation, and he begins to punch Lennie.  Then, as Lennie offers no resistance, the cowardly Curley continues to punch Lennie so that he can seem to have overpowered the big man, just as Candy had told George earlier that he would try to do given a chance.  With George's command, however, Lennie reduces Curley to a wimpering victim himself and reverses the situation.  Now, Curley has become even more alienated from the men and lonely since with this incident the men perceive him as cowardly to have attacked Lennie, as well as weak. When she learns of the incident, Curley's wife, too, ridicules him as a loser. And, with the ridicule of his wife, Curley has no one on his side, so he is desperately lonely.

The best place to look for quotes about loneliness occurs in Chapters 2 and 3 of the novel when George and Lennie end up hanging out with Crooks, the black stable buck, and then with Curley's wife.

The most famous quote about loneliness from Of Mice and Men is in Chapter 2:

"A guy goes nuts if he ain't got nobody. Don't make no difference who the guy is, long's he's with you. I tell ya ... I tell ya a guy gets too lonely an' he gets sick."

Chapter 3 is another good place to find quotes about loneliness. This chapter focuses on Curley's wife. She says the following:

"Why can't I talk to you? I never get to talk to nobody. I get awful lonely."

and

"I get lonely ... You can talk to people, but I can't talk to nobody but Curley. Else he gets mad. How'd you like not to talk to anybody."

While all the men on the ranch experience a level of loneliness that's not capable of being comprehended in modern society, the level of loneliness experienced by Crooks and Curley's wife is unique. Crooks is the only black man on the ranch. He's not welcome by the white ranch hands because of his skin color. He is truly alone. 

Meanwhile, the only other character in this novel who is truly alone is Curley's wife. Sure she's married to the boss's son, but she's clearly not receiving the attention she needs. She is the only woman in the entire novel, which makes her loneliness, like Crooks's loneliness, unique.

In John Steinbeck's Of Mice and Men, Candy is isolated. This is due in part to the situation that exists for all of the men at the ranch. They, like many others, must travel across the country trying to find work in light of the Stock Market Crash of 1929, which started the Great Depression in the United States. They don't have a place to call home or their own.

The other reason is that Candy is disabled: missing a hand. As long as he can work, he will be allowed to stay. When he cannot stop his dog from being shot, it is clear to him that once he is too old, or has outlived his usefulness, he will be let go without a second thought.

As we read the story, we find out that the dream Lennie and George have really appeals to Candy as well. He has saved a large sum of money and offers to help buy the land so that they can all have a life of meaning; he, too, wants to stay in one place and harvest his own crops instead of doing it for someone else as he has done for so long.

Everybody wants a little bit of land, not much. Jus' som'thing' that was his. Something' he could live on and there couldn't nobody throw him off of it. I never had none. I planted crops for damn near ever'body in this state, but they wasn't my crops, and when I harvested 'em, it wasn't none of my harvest.

Working with the men on the ranch, Candy knows that he will not be able to stay there forever. One day he will be out of work, and with his disability, what will he do? So he puts in his lot with George and Lennie, pursuing the American dream of the 1930s.

Your question had to be edited because it asked more than one question. Please remember that you can only ask one question each day. I have focused your question on the theme of loneliness, and I thought it would be interesting to explore this key theme through the eyes of one character in the novel: Candy. There are no direct quotes that clearly state that Candy is lonely, rather you have to infer his loneliness from what he says and does. For example when he overhears George telling Lennie about the dream of owning a patch of land, he is eager to jump in and join them in this dream, offering his own money to help them purchase some land:

"Tell you what -" He leanded forward eagerly. "S'pose I went in with you guys. Tha's three hundred an' fifty bucks I'd put in. I ain't much good, but I could cook and tend the chickens and hoe the garden some. How'd that be?"

He is even willing to leave his money to George and Lennie if he dies. We can see here his desperation for companionship and fellowship because of his loneliness.

Likewise we can infer his loneliness by his reluctance to let his dog be shot. He tries again and again to put of Carlson from shooting his dog, and he reveals the friendship he has had with him:

"Well - hell! I had him so long. Had him since he was a pup. I herded sheep with him."

His reluctance to let his dog be killed and the way he keeps on trying to change the subject and put Carlson off clearly indicates how important this dog is to Candy - he only friend. Of course, the dog killing clearly foreshadows the final killing of Lennie and the loneliness into which George will plunge.

The Great Depression of the 1930s saw many men leave their families when they could no longer provide for them.  They became "bindle stiffs," riding the railroad cars to California where they became itinerant workers on the large corporate-owned farms.  Alienated from family and home, these disposessed men often became paralyzed emotionally.  John Steinbeck wrote of Lennie Small, whom he created to express this paralysis,

"Lennie was not to represent insanity at all but the inarticulate and powerful yearning of all men."

Steinbeck turned to the ideology of socialism as a solution to man's alienation.  With the motif of the fraternity of men that socialism brings, Steinbeck has his characters seek a sense of belonging and hope with one another. For George and Lennie, who already have each other, it is also their dream of owning a ranch that propels them; likewise Old Candy begins to have hope for his future when he thinks of joining in on George and Lennie's plans.  Even the Crooks, the doubly alienated stable worker, sheds some of his despair after he learns of the dream ranch in which he may become a partner.

But, outside of the dream, George and Lennie are still just itinerant workers who must be cautious in their speech and actions so that they can keep their jobs.  Worse yet, the boss's belligerent son, Curley, acts as an opposing force to George and Lennie's friendship and happiness by harassing Lennie until Lennie is instructed by George to "let him have it," and he crumples Curley's hand.  Of course, when Curley's wife tempts Lennie and he accidentally breaks her neck, the friendship of the two men is endangered; then, after Lennie's death, George knows the dream, too, is dead and he is so terribly alone.

Likewise, Curley's wife, who is merely a genitive of Curley, acts also as an opposing force; this time she is a temptress, an Eve as it were, interfering with the fraternity of the men. She and her husband illustrate difference as they both are outside the fraternity of the men.

Old Candy, crippled by having lost a hand, spends his days sweeping and cleaning up the bunkhouse.  He worries that the boss and the others may feel that he is like his old dog and has outlived his usefulness. He tells George and Lennie that he will make a will and leave his share to the others if they let him buy in on their dream.  When he discovers Curley's wife and George leaves, Candy kneels by her'

"You...tramp....You done it di'n't you? I s'pose you're glad.  Ever'body knowed you'd mess things up.  You wasn't no good.  You ain't no good now, you lousy tart.....I could of hoed in the garden and washed dishes for them guys."

Crooks, isolated from the society of his home town, is doubly alienated as he is made to live in the stable alone because he is black.  Hostile at first at Lennie who steps into the barn, he later tells Lennie that he feels as though he is "goin' crazy" because he has no one to talk to or to compare things by. Crooks expresses his terrible aloneness,

"A guy goes nuts if he ain't got nobody.....I tell ya a guy get too lonely sn' he get sick."  ....Sometimes he get thinkin', an' he got nothing to tell him that's so an' what ain't so....He can't turn to some other guy and ast him if he sees it too.  He can't tell. He got nothing to measure by."

Alienated from their own communities and from those they work with, the bindle stiffs of the ranch in Of Mice and Men experience a terrible loneliness.

In the 4th section, or chapter 4, Crooks character is clearly defined. The fact that Crooks has accumulated lots of books shows that he is used to being alone because no one wants to be with him. Being into reading is one way to avoid lonliness. Then, as he begins to talk with Lennie, at first he doesn't want Lennie near him. Lennie really doesn't mean any harm, but Crooks is used to white guys harming him. This guardedness further develops Crooks' lonliness. As you get further into the chapter, you see that Crooks is almost eager to make fun of Lennie because he doesn't have anyone to do that to. He tells Lennie how easy it would be to befriend someone like Lennie because a Lennie wouldn't go tell secrets. He further tells Lennie about his family was alone. He has a few words that really demonstrate his longing for friendship which conversely demonstrates lonliness:

"The thing is, they're talkin' or they're settin' still not talkin'. It don't make no difference, no difference."

Crooks would really like someone to just "set with". But he can't because the guys think he stinks.

One Biblical theory or symbol in Steinbeck's work that reflects loneliness would be the sacrificial lamb.  Lennie has to be the sacrificial symbol in order to placate the mob that is pursuing him.  This position is a very lonely position, symbolized by how Lennie's dreams are essentially all that keeps him company at the end.  Another Biblical theory in Steinbeck's work that indicates loneliness would be the unenlightened masses.  As Jesus is on the cross, he calls out to the heavens and asks "forgiveness, for they know not what they do." Certainly, Carlson and Curley are forces that "know not what they do." They are forces that reflect a condition of loneliness because they are deprived of enlightened understanding.  Finally, I think that the overall lack of spiritual guidance in all of the characters contributes to a sense of loneliness that hovers over them all.  The Biblical theory of the relationship between individual and God is that if an individual takes God in their heart, they are not alone.  Those who do not are condemned to be alone. This theory is evident in Steinbeck's work.  All of the characters lack a spiritual foundation and because of this, their punishment is to be condemned to loneliness.

This isn't a question with a cut-and-dry answer. I would say you could make a good argument in favor of several characters—Crooks springs first to mind, but one could also argue that Candy is a very lonely character, given his advanced age, which sets him apart from the rest of the workers. You could also argue that Curley's wife, despite the fact that she flirts with other men (particularly Slim), is the loneliest character, as the sole woman and someone who is ignored by her husband, the person who is supposed to care about her most. The most important thing, when you're asked to write an ACE-IT paragraph like this, is to choose your argument and stick with it, giving the best evidence you can for it.

As an example, let's say we're going to argue that Crooks is the loneliest character. That's your assertion.

Next, we need to give some context and citation. That means we need to explain who Crooks is and use some quotations from the book to demonstrate that he's lonely. Crooks is described as "the Negro stable buck," the only black worker in the story. On Saturday night, Lennie finds him sitting alone in his room. Crooks tells Lennie that he "ain't wanted" in the bunkhouse with the other men, and explains why: "I can't play because I'm black. They say I stink. Well, I tell you, you all of you stink to me."

Explication and interpretation is the part where you explain how the quotations you've chosen indicate that Crooks is lonely—or rather, how your citations support your assertion. In this case, we can argue that Crooks is forced to keep to himself; he can't have any friends among his supposed peers, because they have unfairly rejected him based on the color of his skin. In turn, Crooks has dealt with this by deciding he doesn't want to be around them anyway—they all "stink" to him. Furthermore, because he's a "cripple," this isn't a situation he can easily find his way out of. He's stuck in it; he's a "permanent" resident in a place where he isn't wanted. Because he sees no escape route, his loneliness is intensified.

In your conclusion, then, you draw together the ideas you have already put forward and summarize what you are saying. You may wish to acknowledge early in your paragraph that Crooks is not the only candidate for the position of "loneliest" character. If so, you could reiterate that here, but also reiterate the key reasons why he is lonelier than the others—for example, although Curley's wife is the only woman, she is white and therefore able to fraternize, even if she can't spend time with the person she really cares about. Crooks, on the other hand, is racially isolated and has nobody to turn to. His loneliness, moreover, is something he seemingly cannot escape from, and its ongoing status means that he becomes more and more lonely as time passes.

Curley's wife is unique in that she has no identity. She is just a pretty small town girl with dreams of "the big life" elsewhere. She longs for celebrity, to make a name for herself 'in pi'tures.' Then she would really live; she would exist.

Of course she would have a first name in the story, but Steinbeck intentionally does not give her one. As an author he "creates" her this way. By simply calling her 'Curley's wife' he portrays her insignificance and social 'non-existence.' Curley can go whoop it up with the whores in town, but his wife must 'stay put' at home as a static object, much as a piece of furniture. She isn't even supposed to talk to the workers on the farm unless spoken to.

Curley's wife is unique in that everyone else (on the farm and in the world) at least has a name.

There are several characters to choose from to answer this question. George, Candy and Crooks each possess different, unique qualities of loneliness in the context of the story. 

George is the only character of these three who has a friend, Lennie. Despite the presence of a companion, George remains isolated. Unlike the other migrant workers he encounters, George must look after Lennie and protect him. This burden compromises the single virtue presented by a migratory life for George - freedom. 

Candy has no friends after the loss of his dog and he is not respected on the ranch. Though Candy takes up with George and Lennie, he sees the possibility of buying land with them disappear when he finds Curley's wife's body in the barn. Candy's loneliness is heightened by the fact that he is old and can no longer work and has litte hope for a positive change in the future. 

Candy is the old, disabled ranch hand who is helpless to stop the shooting of his dog and who knows that he too will be banished when he is no longer useful.

Crooks is the most literally isolated character in the book, isolated by color and living conditions, but he is not a migrant like the others.

Crooks, the despairing old Negro stable worker, lives alone in the harness room, ostracized from the ranch hands. 

In the permanent qualities of Crooks ostracism and in the permanance of his skin color, Crooks is quite different from George, Candy, and Slim who move from place to place, open to the possibility of change. 

Almost every character in Of Mice and Men is lonely.  George’s partnership with Lennie seems like an example of desperation againt loneliness to me!  George and Lennie partner together and are friends because each keeps the other company.

Slim looked through George and beyond him. “Ain’t many guys travel around together,” he mused. “I don’t know why. Maybe ever’body in the whole damn world is scared of each other.”

“It’s a lot nicer to go around with a guy you know,” said George. (ch 2)

Curley’s wife is “married two weeks and got the eye” (ch 2) meaning she is already looking at other men.  She is lonely because her husband sees her as a trophy and not a companion, and she has no friends.  It is because of this that she talks about her dreams, wanting to be in pictures.

Candy is also lonely.  He is old, and feels worthless.  He keeps his old dog with him.

The old man squirmed uncomfortably. “Well—hell! I had him so long. Had him since he was a pup. I herded sheep with him.” He said proudly, “You wouldn’t think it to look at him now, but he was the best damn sheep dog I ever seen.” (ch 3)

Candy needs the dog for company.  He compares his fate to the dog, because he is old and he feels he will soon be worthless too.

I would agree with this statement.  Loneliness is a theme in the book and it is clearly seen everywhere.  Slim, an observant character, makes this point when he sees that George and Lennie travel together.  He even gives his guess as to why people are alone.  He says:

"Ain’t many guys travel around together,” he mused. “I don’t know why. Maybe ever’body in the whole damn world is scared of each other.”

It does seem that people in the book see each other as threats.  So, people are alone.  For example, Curley is threatened by all the men on the farm.  He fears that people do not respect him.  He also fears that his wife might cheat on him. The other men fear as well.  Candy fears what the others think of him, as he is getting old.  George is constantly worried about what others think of Lennie. In light of these example, Slim's observation might be correct.  

The upshot of all of this is that people stay away.  They don't do anything productive to overcome their loneliness.  Hence, they continue to be lonely. No one seeks to build relationships, communities, or anything resembling friendships.

Reflective of the most lonesome of eras in the history of the United States, the Great Depression, John Steinbeck's novella, Of Mice and Men is populated with characters who are misfits of terrible aloneness.  Certainly, as the only female character in the narrative, Curley's wife is separate, or isolated, from the other characters.  And, that she, also, is lonely is apparent from her actions and speech.

Ironically, Curley's wife's use of her sexuality to entice the men is the very quality which so gravely alienates her from the men.  Upon seeing the girl with

...full,rouged lips and wide-spaced eyes, heavily made up, [and] red fingernails....

George declares her "jail bait" and a danger, instructing Lennie to never speak to her or go near here, reminding Lennie of someone from their past who has spent time in jail because of a woman such as Curley's wife.  The others avoid her because she is the wife of the boss's son; they can more easily go to "Susy's place" in town where for "Two an' a half" they can have their desires satisfied without worrying about the husband or their jobs. Curley's wife's lack of a name in Steinbeck's work indicates that she is perceived only as a woman who is a temptress, an Eve of sorts.

In another ironic twist, Curley's wife has married Curley because she was lonely in her own small town; however, as the only woman on the ranch miles from anywhere, she is yet lonely.  Pretending that she is merely tired of Curley, she tells the men:

Think I'm gonna stay in that two-by-four house and listen how Curley's gonna lead with his left twict [sic], and then bring in the ol'right cross?....

"Awright,, cover'im up if ya wanta.  Whatta I care?  You bindle bums think you're so damn good.  Whatta ya think I am, a kid? I tell ya I could of went with shows.  Not jus' one, neither.  An' a guy tol' me he could put me in pitchers...."

Steinbeck employs the use of light at different points in the narrative to bring out the condition of loneliness.  For example, Lennie wanders into Crooks' room because his light was on.  Crooks' loneliness is illuminated because of light. In a very interesting take on this, it is because of the light that one realizes that Crooks is lonely.  Yet, it is also because of the light that Crooks' loneliness is interrupted.  He is no longer lonely when Lennie enters his room.  Thus, the light is used to both accentuate loneliness and alleviate him from it.

This same paradoxical relationship between light and loneliness is seen in the death of Curley's wife.  When Lennie kills Curley's wife, he immediately recognizes what he has done.  He attempts to cover the body with hay.  Once Lennie does this, he runs away and Steinbeck uses the description of light to illuminate an aspect of Curley's wife's, even though she is no more:  "The sun streaks were high on the wall by now, and the light was growing soft in the barn." As this light grows, Steinbeck uses it to transform her now that she is dead:

Curley’s wife lay with a half-covering of yellow hay. And the meanness and the plannings and the discontent and the ache for attention were all gone from her face. She was very pretty and simple, and her face was sweet and young. Now her rouged cheeks and her reddened lips made her seem alive and sleeping very lightly. The curls, tiny little sausages, were spread on the hay behind her head, and her lips were parted.

The use of light growing on her dead body makes Curley's wife more human and more approachable than ever before.  Light transforms her from being lonely to being alone, independent of the world and not dependent on its broken promises.  Light is what brings out her ultimate loneliness because she is dead.  Yet, light is also what transforms her to be distinct from a world where all she experienced was loneliness.  Like Crooks, light brings attention to her loneliness, but also transforms it.