Themes
Economic Class
There is a definite divide between areas of New York City such as between East and West Egg. It sets up the environment outside of Gatsby's party, but inside everything changes. These parties are much like the speakeasy's of the Roaring 20's in that everyone was equal, no matter the class.
Love
Jay Gatsby's purpose in his life is win back the love of his life Daisy. Almost every action he makes is for Daisy and it dictates how the book plays out. Eventually, Gatsby does win the heart of Daisy, but it is all for nothing because loves nothing more than Gatsby's wealth and possessions. Their relationship brings up the meaning of love and the value of a relationship.
The American Dream
The American Dream can be viewed in various ways, but in this case it includes the promise of wealth if people work hard. The value of this dream is often put into question when characters like Daisy and Tom use their money to manipulate others and get their ways. Also, Gatsby's dream is a symbol for the American dream.