There is widespread agreement that the world is moving from unipolarity to a multipolar system, in which a handful of great powers will hold sway. What is debated is whether this return to multipolarity will be peaceful. This collection of essays does not give a clear answer, but the authors do provide a useful survey of the geopolitical landscape. Several of them explore the security threats and functional challenges that will be the focus of great-power politics in the years to come, including terrorism, nuclear proliferation, and energy security. Others look at the grand strategies of rising powers such as China, India, and Russia. The volume highlights the tension at the heart of twenty-first-century-style multipolarity. On the one hand, power and authority will be more decentralized and the inevitable struggles for influence between the United States and emerging non-Western powers will make cooperation more difficult. On the other hand, the challenges that the great powers will confront in the coming decades will be problems of interdependence, such as the environment and weapons proliferation, and so will require intensified cooperation.