What was the main theme of "The Great Gatsby" by F. Scott Fitzgerald?

Only on the surface is "The Great Gatsby" a love story in the traditional sense, as between Gatsby and Daisy; it is more of a love story between people of the 1920s and money, as well as all the material possessions and appearance of social status that could be obtained by wealth. On a deeper level, Fitzgerald's best known novel is about post-World War I decadence, loss of innocence and moral values, greed and corruption that resulted in the death of the original American dream which is supplanted by the pursuit of so-called happiness in the name of the kind of wild parties thrown every Saturday night by Gatsby. Still deeper is the darkness in Man's heart and soul that leads him to need material happiness, as Daisy does to such a strong degree, and the lust to obtain power and the impression of something more than superficial wealth exhibited by Gatsby's hopeless monetary pursuit of Daisy. No amount of money could buy Daisy's love, if only because of the differences in their social status: that of old money, and that of new money.