Psychopathia Sexualis: A Medico-forensic Study, Twelfth Edition deals with the psychology of deviant sexual behavior. The book discusses the psychology and the physiology of sexual life including anthropological conditions such as Gynecomasty. The author describes general pathology including anesthesia sexualis (absence of sexual feeling), hyperesthesia (abnormally increased sexual desire), paraesthesia (perversion), masochism, sadism, fetishism, and antipathic sexuality. The author also examines homosexuality (as abnormal congenital manifestation), effimination, and androgyny. Special pathology includes the manifestations of abnormal sexual life in various forms and states of mental disturbance. The author discusses dementia, epilepsy, periodic insanity, nymphomania, and satyriasis. He also addresses pathological sexuality and its legal aspects that cover acts of rape, murder with rape, sodomy, cultivated pederasty, lesbian love, incest, necrophilia, or immoral acts on persons under care. The book also contains some case histories that illustrate such deviant sexual behavior. This book can interest behavioral scientists, psychiatrists, psychologists, students and professors in the sciences of human sexuality and behavior.