Is it more dangerous to call something evil or not to? This fundamental question deeply divides those who fear that the term oversimplifies grave problems and those who worry that, to effectively address such issues as terrorism and genocide, we must first acknowledge them as evil. Recognizing that the way we approach this dilemma can significantly affect both the harm we suffer and the suffering we inflict, a group of contributors engages in the debate with this series of essays. Drawing on Western conceptions of evil from the Middle Ages to the present, these pieces demonstrate that, while it may not be possible to definitively settle moral questions, we are still able—and in fact are obligated—to make moral arguments and judgments. Using a wide variety of approaches, the authors raise tough questions: Why is so much evil perpetrated in the name of good? Could evil ever be eradicated? How can liberal democratic politics help us strike a balance between the need to pass judgment and the need to remain tolerant? Their answers exemplify how the sometimes rarefied worlds of political theory, philosophy, theology, and history can illuminate pressing contemporary concerns.