This book explores what we mean when we use the term "perversion." Are we dealing with a sexological classification, a mental disturbance, an ethical deviation, a hedonistic style, or an historical-cultural artifact? The book retraces some of the fundamental stages in the field of psychoanalytic thought-from Freud to Masud Khan, Stoller, and Lacan-and proposes an original approach: that "paraphilias" today are taken as an ethical failure of the sexual relationship with the other. The perversions signal a specific relationship with the other, who is treated not simply as a sexual object, but someone whose subjectivity is ably exploited precisely in order to get a perverse pleasure. Acts, if considered perverse, are understood as a metaphorical re-edition of a trauma, above all sexual, in which the subject (as a child) suffered the bitter experience of exclusion or jealousy.