If you have never read or heard of The Screwtape Letters by C.S. Lewis, I highly recommend it. Even if you have read it, I recommend listening to the audiobook.
This is a collection of letters written by Screwtape to his nephew, who is in training as a temptor on behalf of “the father below”. The narrator is quite entertaining, adding delightfully to the author’s well-crafted art, while leaving the discerning reader/listener with much to ponder in his or her own spiritual life and the spirituality of the world around them.