Your everyday bookmark is generally made of plastic or paper, metal or string, sometimes ornate, more often practical.
But, as librarians can attest, readers use pretty much anything within reach.
"Years ago I found a very old Twinkie," says Chip Ward, assistant director of the Salt Lake City Public Library system. "It was rather flat and still in the wrapper."
Careless bookmarking is a widespread phenomenon.
A peanut-butter-and-jelly sandwich was once discovered inside a book by an Ohio librarian. A dead and very decayed fish was reported by another.
A slice of salami has doubled as a bookmark, as have a gold necklace, a woman's gold watch, Gucci sunglasses and a baby's sock stuck inside a baby book.
And how about those bite marks discovered in a dog obedience training book checked out in Gilroy, Calif.?
Locally, librarians say food remnants and reminders like the Twinkie are commonly discovered inside returned library books: candy and gum wrappers, a tea bag, a dried banana peel — once even a fried egg.
And that's not all.
How about pressed flowers, passports, drivers' licenses, greeting cards, utility bills, junk mail (a natural bookmark), concert tickets, sales tags from clothing, report cards, empty cigarette packs, hair combs, family photographs, tissue paper and bits of newspapers?
An embarrassed Salt Lake library patron recently called to report that he had left his dental bridge inside the tome he'd returned the day before.
Other strange discoveries include a jam recipe in a romance novel and cigarette burn holes in a Dick Francis mystery novel.
Readers have also bookmarked a buck or two.
Paychecks, personal checks and cash — $50 and $100 bills — have been found by local librarians and returned to their owners.
Pete Giacoma, director of the Davis County Library, said one of the strangest things he recalls librarians finding in returned books was a $10 bill — and not just any $10 bill. Giacoma said it was a piece of antique currency that had not been in circulation for many years.
Librarians never could track down the bill's owner.
Davis librarians have also come across honor roll certificates, bank statements, library cards, toothpicks, rubber bands, Kleenex and toilet tissue, gum, business cards, a wrist chain, credit cards, bandages, cross-stitch work, personal letters, Lagoon season passes, playing cards and Popsicle sticks.
Davis County Librarian Deanna Zaugg said she once found a letter to a friend from an adolescent stuck inside a returned book.
"It had bad language, gossip. She'd be grounded for life if she was my kid," Zaugg said.
And while readers like to take books home, insects — and not human bookworms — have been known to actually take up residence inside library checkout items.
A family of brown ants made itself at home inside a Salt Lake City Library CD cover. The critters were evicted; the CD was cleaned and put back on the shelf.
E-MAIL: lynn@desnews.com