This chapter from Dillon's "Introduction to Sociological Theory" explores Michel Foucault's theories on power, the body, and sexuality, highlighting concepts like disciplinary practices, bio-power, and the social construction of sexuality. It examines how institutions and discourses regulate bodies and shape our understanding of sex. The text further discusses the development of queer theory as a challenge to traditional sociological understandings of sexuality, particularly the heterosexual/homosexual binary, and considers its implications for social analysis. The chapter also touches upon the heterosexist bias within sociology and the ongoing debates surrounding the essentialist and constructionist views of sexual identity.