The Library has many books and resources about Great Gatsby. Remember to search Destiny for a full list of titles. Remember that many anthologies will have information about the book and the author but may not show up in a search.
Literature and Its Times
The Great Gatsby The Limits Of Wonder
Class Conflict in F. Scott Fitzgerald's the Great Gatsby by 
World Literature Criticism, 1500 to the Present by 
The Great Gatsby, by F. Scott Fitzgerald by 
Using a SUBJECT search is more effective than a keyword search. With a Subject search you will get a list of books about The Great Gatsby. A keyword word will give you a list about Gatsby but also the novel.
Really great video by John Green (vlogbrothers) talking the American Dream. He touches on some of the metaphors such as the green light, the colour yellow, the eyes, and the Valley of Ashes.