Theme 1: Futility of dreams (examples: George and Lennie come extremely close to realizing their dream of owning their own place, and Lennie's killing Curley's Wife destroys it all. Crooks considers escaping the Tyler Ranch and joining Candy, George, and Lennie in their dream, but loses all hope when Curley's Wife's threat brings him back to his harsh reality. Curley's Wife dreamed of being a movie star but rashly married Curley instead and is stuck on a ranch with no one who appreciates her.)
Theme 2: Friendship (examples: Obviously, George and Lennie represent man's desire for companionship and what it means to sacrifice for a friend. Slim represents a wise confidant--someone George can confide in and discuss Lennie's mistakes and past troubles. Candy and his dog represent that when man cannot find companionship with humans, he will look for it elsewhere.)
Theme 3: Oppression of Women (examples: Curley's Wife does not even have her own name in the novelette. The men think nothing of calling her names and talking harshly to her. She hints at Curley's abuse. Curley treats her like a possession. She feels trapped--at first, when she was willing to marry Curley to escape her mundane existence, and again when she realizes that life on the ranch as a woman still offered her no alternatives.