Here’s a little trick to help you keep your books from getting lost forever. If you’re like me, you get a ton of snail-mail spam, what we used to call “junk mail”. Lots and lots of companies — especially those concerned with getting your money to save the whales, the environment, the lives of endangered pets, etc. — put a few sheets of return address labels, with your name and address on them, in their pleas. (I think the theory is that you’ll feel guilty for using the labels without sending them a donation.) Instead of throwing them immediately into the trash, grab those return address labels and stick them on the inside covers of your books. It might not help you keep them on your shelves, but at least your friend will remember that it was stolen from your library.