This collection of essays approaches the role of demons and the devil in ancient and medieval Christianity from a variety of scholarly perspectives: historical, philosophical, and theological as well as philological, liturgical, and theoretical. In the opening article Gerd Theissen presents a wide-ranging overview of the role of the devil, spanning the Hebrew Bible, the New Testament, and patristic literature. The contributions that follow address texts on the devil, demons, and evil, and are drawn from ancient philosophy, the New Testament, early Christian apologetics, hagiography, and history. Covering primarily the patristic period, the volume also contains articles on medieval sources. The introduction discusses the different angles of approach found in the articles in an effort to shed fresh light on this familiar but also uniquely troubling theme.