What was the last book you had to re-read immediately after you finished it?

This doesn’t often happen to me, anyway…but with Stephenson’s Anathem, wow, when I got to the last page, I knew it was going to happen…I was about to re-read the book over, because it was so incredible…I don’t remember doing that since Harry Potter and the Deathly Hallows.

When was the last time this happened to you? What was the book?