The Archbishop has a new book out on Narnia.  This article discusses it and includes an interview with Williams about Lewis and Narnia.  I enjoy his observations about the stories.  An excerpt:

“Puddleglum’s great statement of faith isn’t saying it doesn’t matter whether it’s true or not. He’s saying I have no means of knowing whether this is or isn’t true… But I know there’s something here that I can’t let go of without letting go of myself.”