These three essays — "The Sexual Aberrations," "Infantile Sexuality," and "The Transformations of Puberty" — are among Sigmund Freud's most important works. Here, Freud outlines the core features of libido theory, his grand view of the psychology of sexuality: sexual perversion is a matter of human nature and "normal" sexual behavior only appears later in life, sexual urges begin in infancy, and these urges turn their attention outward as we mature through puberty. Freud first wrote in 1905 and spent the next two decades making major revisions to the text. This edition offers Freud's complete vision of the sexual self, in the definitive James Strachey translation.