Condemned by critics as "the Bible of the brothel" and "the most demoralising book of the century," Physical, Sexual and Natural Religion (later retitled The Elements of Social Science) was one of the most daring critiques of Victorian morality ever published. Presenting a case for free sexual unions before marriage, widespread contraception and family limitation, use of condoms to guard against venereal disease, and the replacement of Judeo-Christian spirituality with a science-based "religion" (really, a set of humane values) that respected the human body, Drysdale challenged the antisensual currents of his time and anticipated the sexual revolution of the 1960s. His arguments infuriated the medical profession, which contested his views without naming him and subjected his book to constant attack. Nonetheless, Elements was extremely popular, running to thirty-five editions and selling nearly 100,000 copies by the time of the author’s death. The book was particularly appreciated and promoted by the free-thought and birth-control associations, and prominent admirers included Charles Bradlaugh, John Stuart Mill, and Viscount Amberley (Bertrand Russell’s father). Drysdale himself is a fascinating and paradoxical character, a sexually abstinent depressive who urged the joyous duty of sexual exercise on others, and who wrote in a vivid style that recalls the passionate intensity of William Blake. In this carefully abridged edition, the author presents the bulk of Drysdale’s polemic, which has not been reprinted since 1905. He introduces the work with a substantial essay setting out the context in which Elements was written, the influence it exerted, and its relevance to contemporary debates about sex education, control of venereal disease, sexual morality, and the roles of science and religion in society and in our personal lives.