Furthermore, concerning the American Dream in Steinbeck's Of Mice and Men, the disparity between those who have it and those who don't is highlighted.
Curly behaves as he does because he can. He's got the money and, therefore, the power. He has the authority to fire the others on the ranch and uses it. He certainly isn't more intelligent than the others, and is no way a better human being. But he's got the money, and that's all that matters.
And there isn't any way for those who don't have money to get it in the novel. The American Dream is a pipe dream, and the economic system is unfair and leads to injustice.
In this book, the American Dream is represented by the fantasy that Lennie and George share. In their fantasy, they are able to go and get a farm of their own. They are able to live without having anyone else tell them what to do. This is one of the major aspects of their fantasy that they often repeat.
The American Dream is, in part, a dream of being independent and self-sufficient. This is what Lennie and George dream of and what they eventually spread, for a little while, to Candy and Crooks.
In the book Of Mice and Men George and Lenny aspire to own their own land with a little homestead on it. The typical American Dream of their day included having land that belonged to a person and being able to gain some level of economic success.
George often tells Lenny the story about what their goal is when he says to him that one day they own their own piece of land with a ranch and Lenny can have rabbits to tend. They save their money in order to be able to later purchase the land.
When the old man, Candy learns of their dream, he too wants to invest his money in the dream.