Okay--so I try and do a really good job keeping library books in the same place. We have a little basket we keep them in. More often then not that is where they end up and it is easy to return them all to the library.
We needed to go back to the library one last time to return books before our move. I counted all the books and was short two! Of all of the times to be short two right before we move!! I looked and was able to find one... but one was still a mystery. We ran to the library anyways and dropped off the books. I came home and looked once again and thankfully there it was on Lucas' bookshelf. I guess it is one more trip to the library for us.