The three essays in the book, "The Sexual Aberrations, " "Infantile Sexuality, " and "The Transformations of Puberty", are among Sigmund Freud's most important works as they set out a theory of human sexuality that continues to influence us today. Freud sought to link to his theory of the unconscious put forward inThe Interpretation of Dreams (1899) and his work on hysteria by positing sexuality as the driving force of both neuroses (through repression) and perversion. The three essays also included the concepts of penis envy, castration anxiety, and the Oedipus complex.