Several years ago the late Dr. Prince A. Morrow announced that a volume dealing with many of the timely topics of sex-education was to be prepared by the undersigned with the advice and criticism of a committee of the American Federation for Sex-Hygiene; but even before Dr. Morrow's death it became evident that this plan was impracticable. Three members (Morrow, Balliet, Bigelow) of the original committee collaborated in a report presented at the XV International Congress on Hygiene and Demography. Since that time the writer, working independently, has found it desirable to reorganize completely the original outline announced by Dr. Morrow. In accordance with a declaration made voluntarily in a conversation with Dr. Morrow, the author considers himself pledged to devote all royalties from this book to the movement for sex-education. Among the many persons to whom is due acknowledgment of helpfulness in the preparation of this book, the author is especially indebted for suggestions to the late Dr. Prince A. Morrow, to Dr. William F. Snow, Secretary of the American Social Hygiene Association, and to Dr. Edward L. Keyes, Jr., President of the Society of Sanitary and Moral Prophylaxis; for constructive criticism, to his colleagues, Professor Jean Broadhurst and Miss Caroline E. Stackpole, of Teachers College, who have read carefully both the original lectures and the completed manuscript; and to Olive Crosby Whitin (Mrs. Frederick H. Whitin), executive secretary of the Society of Sanitary and Moral Prophylaxis, who has suggested and criticized helpfully both as a reader of the manuscript and as an auditor of many of the lectures delivered at Teachers College. M.A.B. TEACHERS COLLEGE, COLUMBIA UNIVERSITY, December 28, 1915. SUMMARY OF CONTENTS PAGE I. THE MEANING, NEED, AND SCOPE OF SEX-EDUCATION 1 Sec. 1. Sex-education and its relation to sex-hygiene and social hygiene. Sec. 2. The misunderstanding of sex. Sec. 3. The need of sex-instruction. Sec. 4. The scope of sex-education. II. THE PROBLEMS FOR SEX-EDUCATION 28 Sec. 5. Sex problems and the need of special knowledge. Sec. 6. First problem: Personal sex-hygiene. Sec. 7. Second problem: Social diseases. Sec. 8. Third problem: Social evil. Sec. 9. Fourth problem: Illegitimacy. Sec. 10. Fifth problem: Sexual morality. Sec. 11. Sixth problem: Sexual vulgarity. Sec. 12. Seventh problem: Marriage. Sec. 13. Eighth Problem: Eugenics. Sec. 14. Summary. III. ORGANIZATION OF EDUCATIONAL ATTACK ON THE SEX PROBLEMS 90 Sec. 15. The task of sex-education. Sec. 16. The aims of sex-education. Sec. 17. The aims as the basis of organized sex-instruction. IV. THE TEACHER OF SEX-KNOWLEDGE 108