The Interpretation of Dreams by Sigmund Freud

Sigmund Freud's The Interpretation of Dreams was one of the most important books of the 20th century. ... The book represents Freud's first major attempt to set out his theory of a dynamic unconscious, created in childhood, which operates continuously in every human mind.

Psychoanalyst Sigmund Freud believed that dreams allow people to express unconscious wishes they find unacceptable in real life. He drew a distinction between the manifest content and the latent content of dreams. The manifest content is the plot of the dream: who's in the dream, what happens, and so on.