It has been remarked by Professor Wilhelm Ostwald that the problem of homosexuality is a problem left over to us by the Middle Ages, which for five hundred years dealt with inverts as it dealt with heretics and witches. To regard the matter thus is to emphasize its social and humanitarian interest rather than its biological and psychological significance. It is no doubt this human interest of the question of inversion, rather than its scientific importance, great as the latter is, which is mainly responsible for the remarkable activity with which the study of homosexuality has been carried on during recent years.
The result has been that, during the fourteen years that have passed since the last edition of this Study was issued, so vast an amount of work has been carried on in this field that the preparation of a new edition of the book has been a long and serious task. Nearly every page has been rewritten or enlarged and the Index of Authors consulted has more than doubled in length. The original portions of the book have been still more changed; sixteen new Histories have been added, selected from others in my possession as being varied, typical, and full.
These extensive additions to the volume have rendered necessary various omissions. Many of the shorter and less instructive Histories contained in earlier editions have been omitted, as well as three Appendices which no longer seem of sufficient interest to retain. In order to avoid undue increase in the size of this volume, already much larger than in the previous editions, a new Study of Eonism, or sexo-esthetic inversion, will be inserted in vol. v, where it will perhaps be at least as much in place as here.