Under the title "Principalities and Powers" and a number of other synonyms, the New Testament is studded with texts referring to the domination of the world' its institutions, and its "atmosphere" by Satan. These texts are analysed in order to present an overall picture of this spirit of Evil, which by temptation and deception attempts to lead men into sin. Christ's coming is shown as the definitive defeat of the Powers which, with only a future of damnation before them, must make a last effort to inveigle the Christian by disbelief and disobedience away from the victorious Christ. This study is a valuable contribution to a subject which has produced little literature. The author is professor of Ancient Christian Literature and New Testament Exegesis in the University of Bonn.