The 10th-anniversary edition of the book that radical re-evaluated the origins and nature of human sexuality.
Christopher Ryan (Author) Christopher Ryan received his PhD in research psychology at Saybrook Graduate School in San Francisco, focusing on pre-historic sexual behaviour. He has taught at the University of Barcelona Medical School and published both scientific and popular articles and book chapters on human sexuality. Cacilda Jetha (Author) Dr Cacilda Jetha is a practising psychiatrist, specialising in psycho-sexual disorders and couples therapy. She has done field research on sexuality for the World Health Organisation.