My church is currently going through a sermon series called "If There Were an Enemy" based on this book, and I figured it was a good time for a re-read. (I so very rarely re-read books!) This one will really get you thinking, as it's written from a senior demon to a younger one, and is all about how to trip up Christians and "win" them to the dark side, essentially. Really makes you think more seriously about how Satan is at work in our lives, and really helps you to better be on guard.