Sadism and masochism were unknown medical terms until the late nineteenth century, when the psychiatrist Richard von Krafft-Ebing introduced these labels to refer to the very particular, and indeed sometimes quite peculiar, behaviors of some of his patients. Later still, Freud (1905) brought the terms together to produce the label of sadomasochism, which remains in widespread use today to describe sexual activity involving bondage and/or the infliction or receipt of pain or humiliation: a sadist preferring to bind the other, inflict pain and/or humiliation, whilst a masochist preferring to be bound, receive pain and/or humiliation. These acts of description had a much more profound impact than simply drawing public attention to behaviors that have been known for many hundreds of years, however. For with recognition by the medical profession, the people engaged in these practices were at once demonized and subject to the control of the state through the twin arms of the medical and legal professions. Of course, some of the behaviors described by Krafft-Ebing and Freud were nonconsensual acts of violence, perpetrated on unwilling victims. But others were not, instead being fully consensual acts sought out for the pleasure they afforded. This crucial distinction remains at the heart of the dispute over the legitimacy of sadomasochism as a sexual practice/identity that may be pursued by consenting adults.