In the twenty-five years after 1989, the world enjoyed the deepest peace in history. In The Rise and Fall of Peace on Earth, the eminent foreign policy scholar Michael Mandelbaum examines that remarkable quarter century, describing how and why the peace was established and then fell apart. To be sure, wars took place in this era, but less frequently and on a far smaller scale than in previous periods. Mandelbaum argues that the widespread peace ended...