We think of the city as a place where anything goes. Take the sensational fantasies and lurid antics of single women on Sex and the City or young men on Queer as Folk, and you might imagine the city as some kind of sexual playground—a place where you can have any kind of sex you want, with whomever you like, anytime or anywhere you choose. But this book argues that this idea is a myth. Drawing on extensive surveys and interviews with Chicago adults, it shows that the city is—to the contrary—a place where sexual choices and options are constrained. From Wicker Park and Boys Town to the South Side and Pilsen, they observe that sexual behavior and partnering are significantly limited by such factors as which neighborhood you live in, your ethnicity, what your sexual preference might be, or the circle of friends to which you belong. In other words, the social and institutional networks that city dwellers occupy potentially limit their sexual options by making different types of sexual activities, relationships, or meeting places less accessible. To explain this idea of sex in the city, the book develops a theory of sexual marketplaces—the places where people look for sexual partners. It then uses this theory to consider a variety of questions about sexuality. Shedding new light on the city of Chicago, this work recasts our ideas about human sexual behavior.