The main themes are illusion and disillusionment. Gatsby builds an illusion of a perfect life with Daisy, but in the end, he is disillusioned. Social mobility is also a theme. Gatsby tries to move from a lower - class background to the upper class to be with Daisy. And finally, the theme of morality. The actions of the characters, such as Tom's infidelity and Gatsby's illegal activities to gain wealth, raise questions about moral values in the context of the novel.
The themes include the hollowness of the upper class. Despite their wealth, characters like Tom and Daisy are morally empty. Wealth doesn't bring them true happiness. And there's the theme of time and the past. Gatsby is constantly trying to recapture the past with Daisy, which shows how the past can haunt a person. In addition, the theme of appearance vs. reality is there. The glittering parties at Gatsby's mansion seem glamorous on the surface but hide a lot of loneliness and unhappiness.