What is the primary theme explored in "The Screwtape Letters"?

The primary theme explored in "The Screwtape Letters" is the nature of good and evil. This work, written by C.S. Lewis, presents a series of letters from a senior demon, Screwtape, to his apprentice, Wormwood, offering insight into the temptations humans face and the strategies demons employ to lead them away from God and the path of righteousness. Through this unique perspective, Lewis delves into the ethical and moral dimensions of human behavior, illustrating the constant battle between spiritual good and evil forces.

The letters explore how virtues can be distorted into vices, exposing the complexities of sin and the subtleties of moral choices. By emphasizing this ongoing struggle, Lewis encourages readers to reflect on their own moral decisions and the influence of external forces in shaping their character.