In Chapter Four, Steinbeck gives Crooks a thorough introduction, particularly in describing Crooks himself and his living quarters. Since Crooks is black, he is forced to live apart from the other white workers; clearly, racism was a part of this culture and era. Crooks lives/sleeps in a shed attached to the barn. Crooks was also excluded from other things at the ranch. While the rest of the workers are in town, Crooks stays behind claiming he isn't wanted. Having become accustomed to being excluded, Crooks has become a loner himself as if to accept his isolation or to have some control over it.
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.
It is fitting then that Steinbeck gives Crooks his own introduction, thereby presenting him as he is in the novel: somewhat isolated from the others.
Crooks has a back ailment, a crooked spine, and he has to rub ointment on it every night. He must deal with being a social outcast in addition to dealing with a physical ailment. Crooks is one who suffers yet perseveres. And being that he is often isolated, he suffers alone, seemingly with no hope.
So it is unlike Crooks to allow Lennie (and then Candy) into his bunk. And although Crooks initially criticizes Lennie and the dream of owning a farm, Crooks eventually opens up a little bit. Even Crooks, in his solitude has not lost all hope of having a better life. When Candy and Lennie talk more about the farm, Crooks reluctantly offers to help:
He hesitated. ". . . 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-a-bitch if I want to."
Unfortunately, Curley's wife interrupts this moment and after she threatens Crooks, he retreats back to his original demeanor and attitude of being aloof and keeping his distance.
It is fitting that in this chapter, Crooks is befriended by Lennie and Candy. Lennie is a social outcast because he is socially awkward. In his innocence and mental disability, he often gets into trouble, often violent trouble on account of not understanding his own strength. Candy is the aging ranch hand, fearful that he will be too old to work (in the eyes of others) and therefore he feels like a potential outcast (being fired) in the future. All three are treated as different, "other," or unwanted in some way. Crooks is black, Candy is old, and Lennie is mentally challenged. And yet they come together in a fitting place, Crooks' isolated bunk, to discuss one last dream.
Curley's wife interrupts talk of this dream, but her presence is somewhat fitting as well. She later reveals to Lennie that she had dreams herself but married Curley and now finds herself stuck at a ranch with nothing to do but flirt and talk with the other ranchers.
The chapter ends with Crooks rubbing ointment on his back and this symbolizes his reluctant acceptance of his role as the isolated, ailing worker on the ranch. It is more melancholy knowing that Crooks had at least entertained the idea and hope of following George, Lennie, and Candy to a better life on a new farm, a place where he would probably not be persecuted the way he is in his current situation.