Research has shown that by the time they graduate, as many as one in three women and almost one in six men will have been sexually assaulted. But why is sexual assault such a common feature of college life, and what can be done to prevent it? Drawing on the Sexual Health Initiative to Foster Transformation (SHIFT) at Columbia University, the most comprehensive study to date of sexual assault on a campus, Jennifer S. Hirsch and Shamus Khan present an entirely new framework that emphasizes sexual assault’s social roots, based on the powerful concepts of “sexual projects,” “sexual citizenship,” and “sexual geographies.” Empathic, insightful, and far-ranging, transforms our understanding of sexual assault and offers a roadmap for how to address it.