This is the first of three massive volumes that are to appear under this title. In the preface the author presumes that his conclusions will be of revolutionary importance, but adds that they will be arrived at not through argument, and by the direct inference from facts. The facts are certainly there, for the first volume resembles The Golden Bough in its immense collection of detailed information. So far the chapters deal with such topics as the Evolution of Motherhood, the Origin of Love, the Primitive Group, the Matriarchal Phase in Civilized Societies, the Institution of Marriage, Group Marriage and Sexual Communism. We shall reserve a further treatment of the book for the time when the later volumes have appeared, which will embody the author's conclusions.