A boy who knows nothing asks a boy who knows nothing. A girl who knows nothing asks a girl who knows nothing. From nothing nothing comes. Men who have been such boys know nothing. Women who have been such girls know nothing. From nothing nothing comes. They have become familiar with sex circumstances. They are parents. They have done the best they knew how. But they never learned sex. They never realized its fundamentals. The time has come for a book like this to command the attention of medical men, since now an awakened public demands from them, as the conservers of life and the directors of physiological living, explicit directions in everything pertaining to the physician’s calling, not omitting the intimate, intricate, long taboo and disdained details of sex life and procreation.