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.

In addition to the fine quotes already provided, it is important to note that description, counterintuitive as this seems, often conveys emotion. We can perceive Crooks' loneliness in the depiction of how he is forced to live apart from the other men:

Crooks, the Negro stable buck, had his bunk in the harness room; a little shed that leaned off the wall of the barn. ... This room was swept and fairly neat, for Crooks was a proud, aloof man. He kept his distance and demanded that other people keep theirs.

His loneliness comes through too as he says to Lennie:

"I ain’t wanted in the bunk house, 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. ..."

We can imagine the loneliness Crooks experiences at the kind of wholesale rejection he is subjected to because of his race, segregated into a separate room with only a box of straw to sleep in.

Crooks' loneliness reveals itself for a moment in his expression of longing to be part of the ranch Lennie, George and Candy dream of owning. Crooks offers to work for nothing to be part of this community:

“ . . . . If you . . . . guys would want a hand to work for nothing—just his keep, why I’d come an’ lend a hand. I ain’t so crippled I can’t work like a son-of-abitch if I want to.”

Much as Crooks accepts his loneliness, he would give almost anything to end it.

Crooks is the African American stable hand with a crooked back. Unlike the other workers on the ranch, he is prohibited from sleeping and staying in the bunkhouse with the other men because of his race. Instead, he has his own small room attached to the barn, where he lives alone and isolated from the other workers. Crooks is a relatively cantankerous man because of his marginalized status, and he initially treats Lennie with scorn when Lennie first enters his room. However, the reader discovers that Crooks's pessimistic personality is a result of his loneliness and grief. After upsetting Lennie, Crooks reveals his loneliness by telling him,

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? 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.

Crook's statement not only reveals his loneliness and isolation—it also illustrates the theme of friendship and camaraderie. He believes that in order to thrive, one must have opportunities to interact with other people and form valuable relationships. He continues to lament his loneliness by saying,

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.

Steinbeck - Of Mice and Men

Crooks talks about loneliness in Chapter 4.  He says to Lennie,

"Maybe you can see now.  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 and read books...Books ain't no good.  A guy needs somebody - to be near him".

Crooks goes on to say,

"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".

Crooks then states directly that he is describing his own alienation and loneliness.  He says,

"I didn't mean to scare you...I was talkin' about myself.  A guy sets alone out here at night, maybe readin' books or thinkin' or stuff like that.  Sometimes he gets thinkin', an' he got nothing to tell him what's so an' what ain't or not.  Maybe if he sees somethin', he don't know whether it's right or not.  He can't turn to some other guy and ast him if he sees it too...If some guy was with me...then it would be all right.  But I jus' don't know..." (Chapter 4).