Book excerpt: Along with its much vaunted progress in scientific and economic realms, the twentieth century has witnessed the rise of the most brutal and oppressive regimes in the history of humankind. Even with the collapse of Marxism, current instances of "ethnic cleansing" remind us that tyranny persists in our own age and shows no sign of abating. Daniel Chirot offers an important and timely study of modern tyrants, both revealing the forces that allow them to come to power and helping us to predict where they may arise in the future.