The book is divided into three essays, each exploring different aspects of human sexuality:"The Sexual Aberrations": In this essay, Freud discusses what he calls "sexual aberrations," which are deviations from the norm of heterosexual intercourse. He introduces concepts such as fetishism, exhibitionism, voyeurism, and homosexuality, exploring their psychological underpinnings and proposing that these behaviors are rooted in the individual's early development."Infantile Sexuality": Freud introduces the idea that sexuality is present in human beings from infancy. He explores various stages of infantile sexuality, including oral, anal, and phallic stages, and discusses how these early experiences shape adult sexual behaviors and psychological development."The Transformations of Puberty": In this essay, Freud delves into the psychological changes that occur during puberty. He discusses the concept of the Oedipus complex, where children experience unconscious sexual desires for their opposite-sex parent and rivalry with their same-sex parent. Freud also introduces the idea of castration anxiety and penis envy as crucial aspects of psychosexual development.