Analysis of Histories--Race--Heredity--General Health--First Appearance of Homosexual Impulse--Sexual Precocity and Hyperesthesia--Suggestion and Other Exciting Causes of Inversion--Masturbation--Attitude Toward Women--Erotic Dreams--Methods of Sexual Relationship--Pseudo-sexual Attraction--Physical Sexual Abnormalities--Artistic and Other Aptitudes--Moral Attitude of the Invert. CHAPTER VI. THE THEORY OF SEXUAL INVERSION. What is Sexual Inversion?--Causes of Diverging Views--The Theory of Suggestion Unworkable--Importance of the Congenital Element in Inversion--The Freudian Theory--Embryonic Hermaphroditism as a Key to Inversion--Inversion as a Variation or "Sport"--Comparison with Color-blindness, Color-hearing, and Similar Abnormalities--What is an Abnormality?--Not Necessarily a Disease--Relation of Inversion to Degeneration--Exciting Causes of Inversion--Not Operative in the Absence of Predisposition. CHAPTER VII. CONCLUSIONS. The Prevention of Homosexuality--The Influence of the School--Coeducation--The Treatment of Sexual Inversion--Castration--Hypnotism--Associational Therapy--Psycho-analysis--Mental and Physical Hygiene--Marriage--The Children of Inverts--The Attitude of Society--The Horror Aroused by Homosexuality--Justinian--The _Code Napoléon_--The State of the Law in Europe Today--Germany--England--What Should be our Attitude Toward Homosexuality? APPENDIX A. Homosexuality Among Tramps. APPENDIX B. The School-friendships of Girls. INDEX OF AUTHORS. INDEX OF SUBJECTS. SEXUAL INVERSION. CHAPTER I. INTRODUCTION. Homosexuality Among Animals--Among the Lower Human Races--The Albanians--The Greeks--The Eskimos--The Tribes of the Northwest United States--Homosexuality Among Soldiers in Europe--Indifference Frequently Manifested by European Lower Classes--Sexual Inversion at Rome--Homosexuality in Prisons--Among Men of Exceptional Intellect and Moral Leaders--Muret--Michelangelo--Winkelmann--Homosexuality in English History--Walt Whitman--Verlaine--Burton's Climatic Theory of Homosexuality--The Racial Factor--The Prevalence of Homosexuality Today.