The Screwtape Letters is an epistolary satire by C.S.Lewis, wherein the whole plot of temptation and moral conflict in a series of letters is written between the senior demon Screwtape to his novice nephew Wormwood. In their correspondence, Lewis exposes not only the nature of human faith but even the subtleties of human sin and spiritual battles that besiege men. Hilarious and profound all at once, it shows just how easily one can be derailed from virtue. Above all, it provides a powerful reflection on the obstacles to a life of faithfulness.