As in his earlier writings, Seyom Brown displays a tempered combination of vision and common sense. Most of his book is devoted to describing those trends-physical, technological, economic and social-which are changing the nature of international relations. Looking to the future, Brown sees a world in which superpower bipolarity, the cohesion of alliances and the sovereignty of states have all eroded, moving the world toward a system of "polyarchy" with new problems and challenges. Will leaders and nations have the political creativity to deal with them? The importance of the book lies mainly in its potential for helping them to understand the underlying forces at work. Whether the author's specific suggestions point the way is an open question. He makes no exaggerated claims in that respect.