Three Contributions to the Theory of Sex (Drei Abhandlungen zur Sexualtheorie) is a significant work by Sigmund Freud, first published. In this book, Freud lays the groundwork for his broader theory of sexuality, presenting three key contributions to the understanding of human sexual development and its role in psychological life. Though many of Freud’s ideas have been criticized and revised, particularly regarding his views on infantile sexuality and the Oedipus complex, the work remains a foundational text in psychoanalysis and the study of sexuality.