'This book, as is true of my other books, is nothing but a chapter in the "book" being written these past more than thirty years on "sexuality", that is, gender identity and erotics. The large book will, I trust, have more chapters, but no ending. I do not know its plot, its full structure, all the characters, where it is heading, or what is its purpose.The first phase of this continuing project was "Gender Identity"; the second is "Erotics". I think of the term "erotics" as having sexual meanings: a subject for study (such as "economics"); a set of behaviors, including fantasies such as daydreams; dynamics of an aspect of mental life (with underlying biologic dynamics); and people who are "erotics" - the way we say "lunatics" - seen from the perspective of their erotic desire, people such as Sade or my informants, such as Bill, a professional pornographer whom you will soon meet, or Fay, who lives for love, who first arrives at my office with Bill.Getting more involved in studying erotic excitement, I saw that erotic daydreams, including pornography, not only offered a way to understand someone's erotic life but could give a wider view of personality. As, over the years, that awareness grew, I have had to confront my failure to jump in and mine the raw material. What I now know to be my resistance - avoidance - I used to think of as "simply" boredom, disbelief, conviction that these scripted fantasies had no value for theory or its confirmation; unwillingness to get into disreputable stuff that could harm my reputation, and uneasiness about descending into certain dark areas of human behavior and fantasy. And there was no path in that jungle. But the subject was being pushed at me from above by patients and informants and pulled toward me from below by my curiosity. The latter is strong; so the more I understand the dynamics of erotic excitement, the more the fun in exploring people's erotic lives. The clues accumulate.'- From the Introduction
