This book provides information on testosterone and other androgens, and their role in human physiology and pathology. It covers biosynthesis and mechanisms of action and reviews their effects on brain and behaviour, spermatogenesis, hair growth, bones, muscles, erythropoiesis, the cardiovascular system and lipids, erection, and the prostate. Therapeutic uses of testosterone preparations are carefully evaluated, including use in women, the aging male, and its abuse and detection in sport. The book reviews applications in male contraception, the role of 5a-reductase inhibitors and the controversial use of DHEA. For this book the editors have assembled the world leaders in testosterone research and clinical andrology and endocrinology. A special feature of the book is the fact that its 24 chapters were submitted simultaneously to insure rapid publication. This revised and significantly expanded edition will serve as the standard source of reference for many years.