Of Mice and Men, is an excellent piece of literature and one of Steinbeck's best. The novel is about how two workers, George and Lennie, work on a new ranch and attempt to accomplish their dreams. Steinbeck uses the novel as a device to teach people how he feels about 1940s America. In the story, there's racism to African Americans, unfair treatment to mentally disabled people, and women were treated with disrespect. 

Steinbeck wrote this book because he saw the injustice in the world, and this is made clear by the hidden allegories in this novel. The hidden symbols, the innocence of Lennie, and the fact that this story is beyond realistic help to separate this novel from others to make this book a true classic.