An American Tragedy

What is the meaning of the title how does it relate to the book?

The title "An American Tragedy" is a play on the expression "the American dream." That dream is supposedly to rise from rags to riches, or at least to do better than our parents did before us.

In the book, Clyde Griffiths dreams of living a better life. His parents are poor evangelists who shun material wealth. Clyde wants that wealth and everything that goes with it. He tries to get it through working, but he finds an easier way to attain it: marry a wealthy woman. The tragedy is that his dream is a nightmare for those who love him. Clyde will stop at nothing, not even murder, to get what he wants, and he ends up losing everything.

FYI, the book was made into a movie, but the title was changed to "A Place in the Sun." It's an excellent movie.