Leahy presents a lucid, biblical account of Christian teaching on such issues as the existence of angels – good and evil; the present position and strategy of Satan; the witness of Old and New Testament to demonic activity; the demonic in church history; and the challenge of the demons to the church of Christ, especially on the mission field. While taking our ‘adversary the devil’ seriously, Leahy constantly emphasizes the victory of Christ over him, and the fact that, in the words of John Calvin, ‘The whole of Satan’s kingdom is subject to the authority of Christ.’