Book excerpt: Satan worship. Witches. New Age channelers. The last two decades have witnessed a vast upsurge in occult activity. Scores of popular books have warned Christians of the dangers and urged them to do battle against these spiritual forces. Few books, however, have developed a careful biblical theology on demons, principalities and powers. Clinton Arnold seeks to fill this gap, providing an in-depth look at Paul's letters and what they teach on the subject. For perspective, he examines first-century Greek, Roman and Jewish beliefs as well as Jesus' teaching about magic, sorcery and divination. Arguing against many recent interpretations that have seen principalities and powers as impersonal social, economic and political structures, Arnold contends that the New Testament view is that such forces are organized, personal beings which Jesus defeated at the cross and will bring into full subjection at his return. In his concluding section Arnold suggests practical ways in which Christians today can contend with the forces of evil. A thoughtful, biblical look at an urgent challenge facing the church.