C.S.Lewis (1898-1963) was a learned man who also became a very popular writer. In The Screwtape Letters a senior demon is instructing his nephew, a novice, how to tempt an ordinary man so that he loses his soul. C.S. Lewis was a member of the Anglican Church, which is close to Roman Catholic theology.
In our scientific era, we are encouraged not to believe in spirits interfering in human life. A person can say he or she is a religious or spiritual person and not believe in spirits. Apparently C.S.Lewis's time was a transitional period in which many belief systems were in existence simultaneously. For example, Lewis himself was an atheist for a while after World War I.
In the Screwtape Letters everything is backwards, and God is referred to as The Enemy. Perhaps the book is a satire; I don't know. In any case, it is very amusingly written; funny and serious at the same time.
