We just discovered what happens when termites get into a box of old books. :(
This happened to me a few years ago. We had boxes of books in the garage that I hadn't unpacked in anticipation of buying new bookshelves (which took far longer than it should have, but that's another story).
Some boxes had good (expensive) hardcover textbooks and cheap, usually second-hand, paperbacks. The termites must've been gourmets, because they only ate the expensive ones, the bastards. I figured I lost somewhere around 2 or 3 thousand dollars worth of books.