These novels also tend to have very memorable characters. In 'Catcher in the Rye' by J.D. Salinger, Holden Caulfield is a character that many can relate to, with his teenage angst and his search for authenticity in a 'phony' world. And the way these characters interact and develop reflects broader American values and ideals.
Well, they often capture the essence of the American experience at different times. For example, 'The Adventures of Huckleberry Finn' by Mark Twain shows the pre - Civil War South and issues like slavery and freedom through the eyes of a boy.