Sigmund Freud helped advance the field of psychology through his revolutionary works and thinking. This has helped to impact how people view the mind and psychological development. Within his Three Essays on the Theory of Sexuality, he focuses on sexuality, primarily the sexuality of infants. Before Freud, many people did not believe that infants could have any inclination towards being sexual in their actions. Freud thought differently and used medical context to help justify the sexual material in his book. The book is split into three parts, the sexual aberrations, infantile sexuality, and the transformations of puberty. Each section explains different aspects of sexuality. They also guide the reader to understand why people are diverse in their sexuality and also why some have deviations within their sexuality. These deviations, when understood, can further be treated by the use of Freud’s psycho-analytical theory.