I recently read C.S. Lewis' The Great Divorce and it was superb. Not only was the prose excellent and witty, the book a coherent and tightly packed critical mass of wisdom, but it was also interesting for its mental images. The Screwtape Letters is probably my favorite book, it's very insightful on the dynamics of sin, temptation and the notion of having the right attitude. However, it doesn't provide much 'visually'. The Great Divorce provided a strange and yet wonderfully engaging and powerful world in which its events occur, which provided a lovely immersion as I read. I finished it in one day. On the whole, it seemed like the basis for the mother of all concept albums. One of my favorite quotes was:
"What you now call the 'free play of inquiry' has no more or less to do with the ends for which your intelligence was created than masturbation has to do with marriage."