Power and Interdependence introduces the concept of “complex interdependence,” a framework that recognizes the multiplicity of channels connecting societies—ranging from formal diplomacy to transnational organizations and economic exchanges. Keohane and Nye distinguish between “sensitivity interdependence” (how quickly and significantly changes in one country affect another) and “vulnerability interdependence” (the costs of adjusting to those changes), arguing that these forms of interdependence can be sources of both power and constraint. The book uses a wealth of historical and contemporary examples, such as the 1975 oil crisis and the evolution of international monetary policy, to illustrate how states leverage economic and institutional ties to achieve their goals without resorting to force.

A key insight is that, in a world of complex interdependence, issues like trade, environmental protection, and development aid can be as important as military security. Keohane and Nye challenge the realist assumption that military power always dominates, showing that the use of force can disrupt mutually beneficial relationships and often carries prohibitive costs—especially among advanced democracies. They also analyze the changing distribution of power in the international system, using analogies from economics to describe unipolar, bipolar, and multipolar structures, and emphasize the growing importance of international organizations and regimes in managing global affairs.