This book dealt chiefly with congenital inversion, publishing no new cases, but revealing a wide knowledge of the matter.

Raffalovich put forward many just and sagacious reflections on the nature and treatment of inversion, and the attitude of society toward perverted sexuality.

The historical portions of the book, which are of special interest, deal largely with the remarkable prevalence of inversion in England, neglected by previous investigators.

Raffalovich, whose attitude is, on the whole, philosophical rather than scientific, regards congenital inversion as a large and inevitable factor in human life, but, taking the Catholic standpoint, he condemns all sexuality, either heterosexual or homosexual, and urges the invert to restrain the physical manifestations of his instinct and to aim at an ideal of chastity.

On the whole, it may be said that the book is the work of a thinker who has reached his own results in his own way, and those results bear an imprint of originality and freedom from tradition.
In recent years no one has so largely contributed to place our knowledge of sexual inversion on a broad and accurate basis as Dr.Magnus Hirschfeld of Berlin, who possesses an unequalled acquaintance with the phenomena of homosexuality in all their aspects.