When first published in French, the first volume of The History of Sexuality bore the subtitle La Volont de Savoir ("the will to knowledge.") Foucault is not interested in sexuality itself so much as he is interested in how it has become an object for knowledge. Why, in the past few centuries, have we increasingly come to see our identity as bound up with our sexuality? Why have we come to study sex with such great interest?
Foucault follows what has been called a "genealogical method" with regard to sexuality. He does not assume that the concept of sexuality denotes something fixed. Instead, he follows a trail that suggests that our concept of sexuality has carried a number of different meanings, has been used in a number of different ways, and has served a number of different purposes. There is not a fixed "thing" that is our sexuality. Rather, sexuality has been employed as a tool for distributing certain kinds of power.
In particular, Foucault sees the proliferation of discourses on sexuality as a means of social control. We have connected the concept of sexuality to education, psychiatry, family structure, demography, good government, and much else besides. Because sexuality has been so closely linked to confession, and hence to self-scrutiny and self- analysis, this self-scrutiny and self-analysis has been extended to every aspect of our life. In the interests of a "healthy" sexuality, we keep a close watch and control over our own behavior and the behavior of others.
Sexuality, according to Foucault, is nothing more than a social construct. There is not something about our sex organs, or the act of sexual intercourse, or our instincts and impulses related to that act, that in itself relates to other aspects of our consciousness and social being. Rather, we have created connections that we now think of as objectively real and independent of us. Foucault takes a "constructivist" position toward sexuality, as opposed to an "essentialist" position, which would see sexuality as something fixed that exists in us.
Near the end of the book, Foucault likens sexuality in our age to astrology in earlier ages. People used to see a great variety of events as hinging on, and explained by, the movement of the stars. Astrology draws on the simple facts about the movements of heavenly bodies and draws a complex series of connections between these movements and other events in the world. Similarly, some simple facts about sexual behavior have been taken to explain a wide series of facts about events and ideas in the modern world. Foucault traces the curious history according to which sexuality has been connected to the confession, to psychiatry, to demography, and so on.
Foucault also emphasizes the contingency of the history of sexuality. Sexuality has not become an important concept through any grand historical design. There has been a seemingly random sequence of events that has drawn sexuality into the forefront of our modern consciousness.