The Screwtape Letters by CS Lewis

Dedicated to Lewis’s friend and colleague J.R.R. Tolkien... The narrative takes the form of a series of letters from Screwtape, a devil high in the Infernal Civil Service, to his nephew Wormwood, a junior colleague engaged in his first mission on earth trying to secure the damnation of a young man who has just become a Christian. Although the young man initially looks to be a willing victim, he changes his ways and is ‘lost’ to the young devil.