In the Great Gatsby, what is the theme?
The theme of The Great Gatsby is the failure of the American dream and the loss of innocence. Gatsby, like the early settlers in America, had yearned after something transcendent -- symbolized by the green light on the end of Daisy's dock that Nick sees him stretching out his arms towards at the end of Chapter One. Gatsby's failure and death embody the decline of idealism and the rise of the selfish crassness of the Buchanans, as Nick makes clear in his remarks in Chapter 9:
And as the moon rose higher...gradually I became aware of the old island here that flowered once for Dutch sailors’ eyes—a fresh, green breast of the new world....for a transitory enchanted moment man must have held his breath in the presence of this continent, compelled into an aesthetic contemplation he neither understood nor desired, face to face for the last time in history with something commensurate to his capacity for wonder.
And as I sat there brooding on the old, unknown world, I thought of Gatsby’s wonder when he first picked out the green light at the end of Daisy’s dock. He had come a long way to this blue lawn, and his dream must have seemed so close that he could hardly fail to grasp it. He did not know that it was already behind him....
Nick honors Gatsby alone of all those he meets because of this capacity to live beyond himself, his wonder and longing, but the capacity is gone in society as a whole. Hedonism, shallowness, and selfishness have killed the American Dream.
Themes that are present in The Great Gatsby include: social class and the shallowness of the rich.
"They were careless people, Tom and Daisy -- they smashed up things and creatures and then retreated back into their money or their vast carelessness or whatever it was that kept them together, and let other people clean up the mess they had made" (188).