Over the last half century, champions of state sovereignty have been on the defensive. Global flows of goods, people, and ideas have eroded the autonomy and the authority of states. The human rights revolution and liberal internationalist notions about the "responsibility to protect" have given the international community more say in what goes on inside of states. Almost all the problems of the twenty-first century -- threats to the environment, health epidemics, nuclear proliferation, terrorism -- seem to demand solutions that abridge or diminish norms of state sovereignty. Standing against the tide, this provocative volume provides one of the best recent efforts to reiterate why state sovereignty remains vital to a working, cooperative international order. In a clever move, the book asks the question of what international politics would look like without sovereignty. Its argument is that state sovereignty is a deeply functional and moral political value that allows societies to make choices and render international organizations accountable -- as the editors argue, "to act as sovereign is to claim the mantle of responsibility." A skeptic could argue that many of the international rules and institutions of the modern age do not really challenge state sovereignty but in fact strengthen the ability of states to respond to domestic aspirations. But in any case, the debate this book will trigger is welcome and essential.