"The Screwtape Letters" by C.S.Lewis is a religious satirical novel giving the devil's perspective of Christian life and topics. The story is in the format of letters from the devil Screwtape to his nephew, Wormwood, who is training to be a demon.
Screwtape's letters concern a person who has converted to Christianity, whom Screwtape calls "the patient." Screwtape is trying to help the incompetent Wormwood to influence the convert away from Christianity to bring him into Hell. He advises his nephew to tempt the man away from thoughts of God to selfish thoughts and doubts about God. Instead, the man becomes involved with a Christian girl and becomes more devout. At the end, Screwtape observes that modern people in Hell are less major sinners than materialistic conformists who lose sight of God.