When discussing the thematics of Steinbeck's novel, we would do well to first examine the title, which is an allusion to a line of Robert Burns, a Scottish poet: "The best laid schemes o' mice an' men gang aft aglay." Translated into modern English, the verse reads: "The best laid schemes of mice and men often go awry." This cynical statement is at the heart of the novel's action and serves as a foreshadowing prophecy of all that is to come. For, indeed, the novels two main characters do have a scheme, a specific dream of changing their current way of life in order to have their own place and work only for themselves. The tragedy, of course, lies in the fact that no matter how elaborately our heroes plan, regardless of how intensely they hope and dream, their plan does not find fulfillment.
This is a novel of defeated hope and the harsh reality of the American Dream. George and Lennie are poor homeless migrant workers, doomed to a life of wandering and toil in which they are never able to reap the fruits of their labor. Their desires may not seem so unfamiliar to any other American: a place of their own, the opportunity to work for themselves and harvest what they sow with no one to take anything from them or give them orders. George and Lennie desperately cling to the notion that they are different from other workers who drift from ranch to ranch because, unlike the others, they have a future and each other. But characters like Crooks and Curley's wife serve as reminders that George and Lennie are no different from anyone who wants something of his or her own.
All the characters (all the ones that Steinbeck has developed, at least) wish to change their lives in some fashion, but none are capable of doing so; they all have dreams, and it is only the dream that varies from person to person. Curley's wife has already had her dream of being an actress pass her by and now must live a life of empty hope. Crooks' situation hints at a much deeper oppression than that of the white worker in America-the oppression of the black people. Through Crooks, Steinbeck exposes the bitterness, the anger, and the helplessness of the black American who struggles to be recognized as a human being, let alone have a place of his own.