The chapter in which Crooks is introduced contains the following sentence:
And scattered about the floor were a number of personal possessions, for, being alone, Crooks could leave his things about, and being a stable buck and a cripple, he was more permanent than the other men, and he had accumulated more possessions than he could carry on his back.
Most of the things Crooks possesses seem to be valueless. No doubt he picked up many things that were left behind by workers who only stayed at the ranch temporarily. He has several pairs of shoes, but these could all be discards. If a bindlestiff bought a new pair of shoes, he might want to get rid of his old pair rather than add them to the weight he had to carry when he hit the road. The same might have been true of the rubber boots and the big alarm clock. A big wind-up alarm clock could be bought brand-new in a drugstore for one dollar. A used one probably wouldn't be worth ten cents, because those clocks did not keep good time for very long. It is hard to guess how or why Crooks got a shotgun. He might have thought of having it for self-protection. He may have bought it for a few dollars from some guy passing through. The author never tells how much salary Crooks receives, but he probably does not get fifty dollars a month like the other men, and he may not even think he deserves that much, since he is so badly crippled. Most of the tools and tackle for horses must belong to the ranch, not to Crooks. The ranch boss may pay for his personal medicine, as he should. Besides his food and shelter, Crooks may only receive around twenty dollars a month in cash wages.
The books sound like a lot of junk. Crooks probably didn't pay for any of them but just salvaged them after they had been abandoned or discarded. He probably had to pay for the large gold-rimmed spectacles because his vision was deteriorating. The California civil code for 1905 is an example of the kinds of reading material he owns. It is outdated and totally valueless. The tattered dictionary could not be sold to a book dealer for even five cents. The "battered magazines" are the kind Crooks would take after all the other men had read them. The few "dirty books" are not pornographic but simply dirty. Old books in bad condition are valueless, except to a man like Crooks who has little money and spends a lot of time reading.
Books were very cheap in the 1930's. Many sold brand-new for one dollar. These would include most mysteries and westerns. Used book dealers have always had racks of old books out in front of their shops. These are intended to stop passers-by and lure them inside where the more expensive books are kept. The books out in front, then as now, would be faded and no longer of any interest to most readers. The book dealers wouldn't care whether they were stolen or not. Crooks might have gotten his tattered dictionary that way. He would need a dictionary because there would be many words he didn't understand. It seems pitiful that he was trying to educate himself under such conditions. However, it would seem that he is more articulate than most uneducated black men of his day, and perhaps more articulate than many of the white ranch workers. Solitude has some advantages. He has learned vocabulary and ideas from his reading. He would be a good talker if he had an opportunity to talk with the other men, but he is ostracized because of his race.
Crooks probably collects things because it fosters the illusion that he is an owner of property. He is a pathetic figure, but he had a great deal of pride. His possessions are as much for "show" as they are for his personal use. Steinbeck takes some time to describe Crooks' possessions because they symbolize the unfortunate man's characters and his plight.