Franco De Masi, a psychoanalyst and supervisor of the Italian Psychoanalytic Society, is known for his research on psychotic phenomena. His book on perversion presented here offers numerous insights and guidance for a better understanding of the complex processes and experiences involved in perverse relational moments and structured sexual perversions. De Masi examines the relationship between sadomasochism and other psychological conditions, such as depression, psychoses, and borderline disorders, and discusses the nature of evil in light of various psychoanalytic approaches.