When asked to describe wartime atrocities, acts of terrorism, and serial killers, many of us reach for the word 'evil'. But what does it mean to say that an action or a person is evil? Some philosophers have claimed that there is no such thing as evil, and that thinking in terms of evil is simplistic and dangerous. In response to this sceptical challenge, Luke Russell shows that concept of evil has a legitimate place within contemporary secular moral thought. In this book he addresses questions concerning the nature of evil action, such as whether evil actions must be incomprehensible, whether evil actions can be banal, and whether there is a psychological hallmark that distinguishes evils from other wrongs. Russell also explores issues regarding the nature of evil persons, including whether every evil person is an evildoer, whether every evil person is irredeemable, and whether a person could be evil merely in virtue of having evil feelings. The concept of evil is extreme, and is easily misused. Nonetheless, Russell suggests that it has an important role to play when it comes to evaluating and explaining the worst kind of wrongdoing.