This book reviews and discusses the most recent advances in the understanding of the molecular genetic pathways of sex determination, with special emphasis on vertebrates. Inter alia, coverage includes the genetics and biochemistry of mammalian sex determination, comparisons with other modes of sex determination, and consideration of the biology of sexual development and of the evolution of sex-determining mechanisms. By bringing together an international and interdisciplinary group of experts whose work is focused on many different aspects of the problem, the book reviews much new and exciting work in this area and serves to identify and stimulate promising new research directions.