How does Steinbeck show racial discrimination with Crooks in Of Mice and Men?

Crooks, referred to as the "stable
buck," is mistreated, insulted, and threatened.

In Section 2 the old
swamper named Candy tellsthat the boss "was sure burned" when George anddid not report
in the morning:

"Come right in when we was eatin'
breakfast and says, "'Where the hell's them new men?' An' he give the stable buck hell,
too."

George patted a wrinkle out of his bed, and sat down. "Give
the stable buck hell?" he asked.
"Sure. Ya see the stable buck's a
n****r."
"N****r, huh?"
"Yeah. Nice fella too . . . The
boss gives him hell when he's mad. But the stable buck don't give a damn about
that."

The boss makes Crooks the "whipping
boy" of the ranch, lashing out at him when he is angry. Crooks is exploited by the ranch
hands on occasions such as Christmas. 

Candy tells George about the boss's
having bought a gallon of whiskey for the men at Christmas time. Crooks was allowed to enter the
bunkhouse, but at the expense of being made amusement for the other men:

"They let the n****r come in that night. Little skinner name of
Smitty took after the n****r. The guys wouldn't let him use his feet, so the n****r got him. If
he coulda used his feet, Smitty says he woulda killed the n****r."

Crooks is treated in an extremely demeaning manner, exploited by
the boss and the ranch hands alike.

Later, in Section 4, Crooks is isolated
in the barn where he is made to live alone with the company of nothing but his books. He keeps a
copy of the California civil code so that he knows his rights. At first, he is mean to Lennie,
but as Lennie talks, Crooks realizes that Lennie is no threat, and he enjoys talking to someone.
He tells Lennie that he has to be alone every night. And when he "gets thinkin'," he
has no one to tell him whether it is true or not.

"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. I seen things out here . . . If some guy was with me, he could tell me I was asleep,
an' then it would be all right. But I jus' don't know."

After Lennie tells Crooks about the little farm that he and George are planning to own,
Candy comes into the barn, talking about their plans. Crooks thinks that he would like to join
them. But, the entry of Curley's wife and her sharp tongue and racial insults end Crooks's hopes
to have a place where he can live in peace with others.