The concept of evil is one of the most powerful in our moral vocabulary, and is commonly used today in both religious and secular spheres to condemn ideas, people, their actions, and much else besides. Yet appeals to evil in public debate have often deepened existing conflicts, through corruption of rational discourse and demonization of the other. With its religious overtones and implied absolutism, the concept of evil seems ill-suited to advancing public discourse and pro-social relations in a liberal democracy, as evidenced by its use in the abortion debate. International relations have also suffered from references to an 'axis of evil.' Recently, however, philosophers have begun reconceptualising evil within a secular, moral framework, using the idea of evil as the worst kind of immorality to inform and shape our responses to issues like torture, genocide and rape as a weapon of war. This book continues this trend, exploring a constructive role for the concept of evil in practical ethics.