It is on a second reading that books really reveal themselves for what they are. You know the big picture so your attention is on the gears that move the world around. You can pick up the subtle clues that the author has left behind and most of all you can really appreciate the writing. Indeed the works of most good authors feel so much better the second time around. I recall reading Harry Potter, the Bartimaeus trilogy, the his Dark Materials trilogy, Lord of the rings as a kid but it was only when I read them again that I took note of themes, leitmotifs that I had not registered the first time around. Indeed anything by Gene Wolfe almost demands that you read it again simply because you cannot possibly understand what is happening the first time around. Every good book deserves to be read twice.
I have found this to be true in life as well. It is only the second time around that we do things properly, it is only the second time around that we avoid making the mistakes that we made the first time. Reminds me of what Fred Brooks said. Make version one first, throw it away, make it again, it will be infinitely better.