While I was a volunteer for our local museum, my job was to archive old books. Pressed within their pages were hidden treasures whose discoveries delighted me. I've recently found a kindred spirit in Michael Popek.

It's happened to all of us: we're reading a book, something interrupts us, and we grab the closest thing at hand to mark our spot. It could be a train ticket, a letter, an advertisement, a photograph, or a four-leaf clover. Eventually the book finds its way into the world-a library, a flea market, other people's bookshelves, or to a used bookstore. But what becomes of those forgotten bookmarks? What stories could they tell?