It has become commonplace to describe the coming era as one of "security interdependence," in which transnational threats render old notions of national security obsolete. In this major new treatise on twenty-first-century global security, Jones, Pascual, and Stedman -- all experienced policy thinkers -- provide a conceptual framework and comprehensive agenda for U.S. foreign policy in a world of security interdependence. Because the United States cannot secure itself at the "water's edge," they argue, it must be actively involved in the world: building partnerships, strengthening institutions, and forging understandings about power and responsibility. The work advances recent thinking about "the responsibility to protect," the notion that state sovereignty comes with certain obligations, and about older notions of "cooperative security," the idea that states need to work together to advance their security goals. What is most innovative is the book's institutional agenda, which comes out of extensive consultations with officials and experts worldwide. This is one of the best efforts yet to provide a coherent synthesis of the security-interdependence worldview.