Inevitably enemies by position and by the incompatibility of their ideologies, the United States and the Soviet Union have a common interest not in ruling together over the world, but in not destroying each other. This book reflects on the problems of attaining peace. Part One deals with theory, the concepts and systems of international relations. Part Two investigates the sociology of peace and war, discussing determinants such as space, resources, and regimes. The history of the global system in the thermonuclear age is discussed in Part Three, and Part Four is concerned with morality, strategy, and the attainment of peace through law.