Anthropological Studies in the Strange Sexual Practices of All Races in All Ages was originally published in 1933.The author Iwan Bloch, has already won a distinguished name in the world of science in the fields, of medical history and anthropology. His extremely important treatise "Der Ursprung der Syphilis," was the result of exhaustive research into this entirely new material. This book is a "by-product" of those investigations. Physicians and jurists, anthropologists and social historians, would be greatly indebted to him, as this work would bring them much nearer to the solution of a problem of compelling and universal interest, the question of the origin, the physiogenesis and psychogenesis of the many forms of sexual anomalies and abnormalities, especially of homosexuality, masculine "uranism" and feminine "tribadism".Iwan Bloch was a German physician of diseases of the sexual system, the author of Origin of Syphilis and Marquis de Sade.