In this sobering spiritual classic, Fr. Godfrey Raupert exposes the subtle tactics by which the devil seeks to ensnare souls and disturb Christian life. Drawing on Scripture, tradition, and documented cases, he explains how evil spirits exploit human weakness, the distinctions between possession and obsession, and the difference between authentic and false mysticism. With clarity and urgency, he addresses common questions about demonic influence and the mystery of God’s permission of evil. Above all, he points to prayer, vigilance, and union with Christ as the surest safeguards, equipping readers to resist temptation and persevere in grace.