Have you ever opened a library or second-hand book to find a trace of a previous reader in a left-behind bookmark? I love it when I come across someone’s marker—it feels like a tiny connection made between me and another presumably like-minded reader.

I’m not the only one who feels this way. I just finished a fascinating little book, ForgottenBookmarks: A Bookseller’s Collection of Odd Things Lost Between the Pages, by Michael Popek.

Popek, who serves as manager of his family’s used-book business, loves his most important task: buying and sorting books. (Lucky!) As he wrote in the introduction, “What I found is that I loved the fact that I could come across nearly anything: a moldy copy of Ulysses, a Victorian-era scrapbook filled with trade cards, a first edition of Steinbeck. This treasure hunt still remains my favorite part of bookselling and led directly to my fascination with forgotten bookmarks.” Popek aptly terms the left-behind page markers “treasures within treasures.” Collecting this ephemera became an unlikely passion for Popek who was surprised to find how interested others were in this unusual hobby. He started his blog forgottenbookmarks.com in 2007 and the book followed from there.

Each spread in Forgotten Bookmarks shows a picture of the marker left behind as well as the cover of the book in which it was found. Popek’s collection includes everything from four-leaf clovers to recipes, postcards, letters (some heart-breaking), drawings, ticket stubs, photos, baseball cards, unused cap gun caps, and a few more unusual items.

Collecting bookmarks is one of my simple pleasures, and though I have plenty of them, I still find myself shoving whatever is to hand into my books to mark my place until I can put in a “real” one. I also have a few books that I like to refer back to from time to time, and I’ve left markers other than bookmarks in some of them. A quick scan of my shelves and I find I’ve used the following to mark my place: a small notebook page with two web addresses I want to check out, a “Non Sequitur” comic strip, a publishing house order form, a page torn from a page-a-day calendar, and a strip of paper with a typed writing quote (“In my view a writer is a writer because even when there is no hope, even when nothing you do shows any sign of promise, you keep writing anyway”—Juno Diaz). I usually make sure I flip through any books I’m returning to the library or trading/donating for anything left behind, but now I’m reconsidering. I might just leave something in the next book I get rid of, as a way of saying hello to the next reader who picks it up.