Is it strange to think that you need a companion for a set of books that take place in a world that doesn't even exist? No, not really. I read the companion thoroughly, then re-read the books, and I can say that they really did add something. There were some jokes (like in "The Magician's Nephew) that needed explaining, and some translations that brought the story a little closer to home. If you love Narnia, you'll love the companion.