Steinbeck focuses on dreams as a key theme throughout the novel. The entire novel is centred around the idea of 'The American Dream', demonstrated through the characters of George and Lennie.
George and Lennie - Primary characters within the novel, who's relationship and aspirations mirror that of the american dream within society at the time. When George shoots Lennie and ends his life, this is symbollic of the unobtainability of the american dream during times of the great depression.
All other characters utilse dreams and aspirations as a form of escape from the mundane and difficult life they are leaving.
Curley's wife - secondary character. Her dream of becoming a film star was not achieved and thus provides an explanation for why she is the way she is as a character.