“For the physician himself, sexual anomalies, treated as they are in a distant manner in text-books on psychiatry, are in greater part a _terra incognita_. Exact knowledge of the causes and conditions of development of sexual aberrations, and of the influence on them of hereditary constitution, education, the impressions of every-day life, and modern refined civilization, is the prerequisite for a rational prophylaxis of sexual aberrations, and for a correct sexual education. Without careful study of the circumstances which attend the _development_ of sexual anomalies, we should never be in a position to use effectual therapeusis. The majority of these unfortunates—Krafft-Ebing calls them Nature’s step-children—are devoid of insight into their malady; like insane patients destitute of understanding of the ethical development of man, they are happy in their abnormal instinctive tendency. For this reason, in spite of the great prevalence of uranism, very few of its subjects seek medical treatment. While the terminal forms of sexual aberrations end in asylums for the insane, the doubtful cases, in which incompleteness of development or apparent viciousness render correct diagnosis difficult, make up the majority. But a thorough knowledge of the aberrations of the sexual instinct is absolutely indispensable to the jurist. The reasons given are thus sufficiently important to demonstrate the need of a hand-book on ‘psychopathia sexualis.’” These words also hold true for English-speaking physicians and jurists,—who can scarcely fail to welcome the translation of a work so systematic and comprehensive as “Psychopathia Sexualis”; a work conceived and executed in the highest scientific and humane spirit; a work which not only broadens and systematizes our knowledge of psycho-sexual phenomena, but also demonstrates, in the results of hypnotic suggestion, how important mental therapeusis must ultimately become in the hands of the physician; a work which is a trustworthy guide in the study of the concrete case of sexual crime, and a philosophical treatise on the inter-relations of sexual criminality, disease, and criminal anthropology. The difficulties of translation have not been slight; but minor errors cannot destroy the author’s meaning. For much encouragement in the work of translation my gratitude to Dr. James G. Kiernan and Dr. G. Frank Lydston, of Chicago, both well-known investigators in this domain of psychopathology, is here expressed; and to Dr. William A. Stone, Assistant Superintendent at the Michigan Asylum, Kalamazoo, I am greatly indebted for assistance in the preparation of the manuscript. CHARLES GILBERT CHADDOCK. ST. LOUIS, MO., November, 1892. TABLE OF CONTENTS. PAGE I. FRAGMENT OF A PSYCHOLOGY OF THE SEXUAL LIFE, 1