In this book, James Sias investigates the psychologies of those who have acted in ways widely regarded as evil, and uses this psychological data as a basis for developing his own theory of evil. Sometimes, he claims, an action is so horrific and despicable that a term like wrong seems to fall short of capturing its moral status. Likewise, occasionally a person’s character is corrupt in such a way that ordinary trait terms like selfish or insensitive, or more general labels like bad or immoral, seem inadequate. In such cases, we often resort to calling the person or action evil. But what does this term mean? What is it that makes a person or action morally evil? Taking a cue from Hannah Arendt, Sias argues that this sort of evil is essentially a matter of regarding others as morally superfluous. In other words, evil is a matter of utter moral disregard. In the course of developing and defending this view, Sias also describes and critiques a number of prominent theories of evil proposed by philosophers in recent years.