it is as follows:

On one side of the little room there was a square four-paned window, and on the other, a narrow plank door leading into the barn. Crooks’ bunk was a long box filled with straw, on which his blankets were flung. On the wall by the window there were pegs on which hung broken harness in process of being mended; strips of new leather; and under the window itself a little bench for leather-working tools, curved knives and needles and balls of linen thread, and a small hand riveter. On pegs were also pieces of harness, a split collar with the horsehair stuffing sticking out, a broken hame, and a trace chain with its leather covering split. Crooks had his apple box over his bunk, and in it a range of medicine bottles, both for himself and for the horses. There were cans of saddle soap and a drippy can of tar with its paint brush sticking over the edge . . .

Crooks's room, if you can call it that, reflects his lowly status on the ranch and in society. As the only African American working on the ranch, he's segregated from the other hands. Whereas they get to share a dormitory, Crooks is forced to sleep in the harness, a cramped little shed that leads off the wall of the barn.

The shed has only a single square window at one side and a narrow plank door leading to the barn at the other. The close proximity of Crooks's room to the barn is telling indeed: it symbolizes the fact that Crooks is considered only slightly above the animals on the ranch. In Crooks's shabby living quarters, not to mention his equally shabby treatment, we see a microcosm of the rampant racial prejudice of 1930s America.

Crooks' room really isn't a room.  It's a small little area in the tack room (a place where ranchers store farming equipment).  The room is filled with all the stuff Crooks has collected in his life.  Therefore, the room is symbolic.  Crooks is not considered a "man" by the people on the farm.  He's just a piece of equipment.  That's why he's out in the barn with all the other pieces of equipment, and that's why he's bent over (like an old, broken down piece of equipment).  Crooks, understandably, becomes excited about the possibility of joining the George/Lenny farm because he thinks that maybe he'll finally have a room to call his own, and he'll finally be accepted as an equal.  The room truly represents how trapped Crooks is in his life, and how little others regard him.

The lengthy description of Crooks' room at the beginning of Chapter 4 tells a lot about his situation as the only black man on the ranch. It is not really his own private room but described as the harness room. It is a lean-to shed attached to the barn. The room is full of leather trappings worn by the horses. Evidently a big part of Crooks' job on the ranch is keeping all this leather paraphernalia in repair. He is accommodated about as well as the horses and mules. His bunk is a long box filled with straw. He has no sheets. He has a few old books and magazines. He does a lot of reading because he has to spend most of his time alone. He apparently does not have a radio. Television, of course, did not exist in those days; it came out after World War II ended in 1945.

The other men won't allow him to come into the bunkhouse. He is naturally very lonely. He confesses as much to Lennie when the big man intrudes. Crooks is only animal-like in that he has more interactions with the horses and mules than with his fellow humans. He is misunderstood in the sense that people believe he is misanthropic and prefers to be alone, when he really would like very much to be able to associate with the other men but has no choice in the matter. He is naturally somewhat angry and defensive. His pride is his only solace.

He is probably right in trying to defend his privacy. When three lonely people--Lennie, Candy, and  Curley's wife--all congregate in his room they create danger and disorder. Crooks knows that his position on the ranch is precarious because of his severe physical impairment. The invaders only remind him that he is better off alone in this tiny sanctuary off the barn.

I think that one of the strongest effects that Steinbeck uses is to describe how compartmentalized Crooks' stable is.  This helps to bring out how his life is one lived in isolation from others.  The segmentation and compartmentalization that is a part of his living condition is reflective of how separated he is from others, helping to drive his own sense of loneliness. When Steinbeck uses the first two paragraphs of the chapter to describe the tools in his room, the overall sense of tidiness, as well as how there is a sanitized feel to the room, one in which medicines and ointments pervade, the effect is to show how Crooks feels about people.  On one level, the effect brings out how Crooks does not trust individuals easily to let them into his own world, one in which order and a sense of control is the only response to a world where his lack of power denies both.  At the same time, there is a controlled element in Crooks' world brought out in Steinbeck's description that displays a sense of hollowness and a sense of emptiness, one that is devoid of human contact.  The overall effect seems to be that individuals cannot find human contact in a world that is controlled and perfectly ordered, reflecting how human emotions are absent.