Offering a consistent, future-oriented perspective, this important new study considers the positions of the United States and other world powers in a changing international system and outlines the priorities and constraints that may govern the conduct of American foreign policy in the decades to come. Focusing primarily on the breakdown of the bipolar system and its replacement by a multipolar system, the authors provide an analysis of great-power relations before and during the Cold War - one that challenges some of the prevailing notions about the lessons of the Cold War, examine the recent changes in international alliances and the future role that transnational actors may take in minimizing conflict, and consider the different arrangements under which this multipolar system can provide the most favorable environment for world peace.