Excerpt from the Preface: "In the study of Love and Pain I have discussed the sources of those aberrations which are commonly called, not altogether happily, "sadism" and "masochism." Here we are brought before the most extreme and perhaps the most widely known group of sexual perversions. I have considered them from the medico-legal standpoint, because that has already been done by other writers whose works are accessible. I have preferred to show how these aberrations may be explained; how they may be linked on to normal and fundamental aspects of the sexual impulse; and, indeed, in their elementary forms, may themselves be regarded as normal. In some degree they are present, in every case, at some point of sexual development; their threads are subtly woven in and out of the whole psychological process of sex. I have made no attempt to reduce their complexity to a simplicity that would be fallacious. I hope that my attempt to unravel these long and tangled threads will be found to make them fairly clear."