Dualistic worldviews and demonic or devilish figures make frequent and varied appearances in both early Jewish and early Christian texts. By setting out the background and charting the development of these notions in Second Temple Judaism, this volume explains New Testament traditions within early Jewish contexts, focusing on issues of the origins of evil and its eschatological removal, the role of eschatological opponents and the function of demons. Textually, the Dead Sea Scrolls and other Second Temple texts are highlighted alongside the Jesus tradition. Four concluding contributions reflect the place of demonological ideas in present theological thought and problems of handling them in church practice.