The end of the Cold War was accompanied by a rush to proclaim the failure of realism as a theory of international politics. The news about the demise of realism is premature, however, as this volume convincingly shows. The articles, previously published in International Security, demonstrate three things. First, the most important, interesting, and relevant work on international relations is still being done within the realist paradigm. Second, within realism the dominant school is defensive realism. Followers of this school (represented in this volume by Charles Glaser and Stephen Walt) believe that the international system is more benign than traditional realists assumed and that states can best attain security by adopting defensive strategies. Third, the major challenge to defensive realism comes from a coalition of "aggressive" realists (such as John Mearsheimer) and modified traditional realists (such as Fareed Zakaria), both more pessimistic about the inevitability of international conflict. Defensive realists argue that aggressive foreign policies are the result of domestic political pathologies (fervent nationalism, unstable ruling elites); aggressive realists contend that the pressures of an anarchic and unpredictable international system, sadly, make the adoption of aggressive foreign policies perfectly rational (although these policies may eventually prove unsuccessful or worse). Other noteworthy articles are written by Christopher Layne, William Wohlforth, and Randall Schweller. Realism is alive and well. This excellent volume will help get the word out.