A bookend is an object that is designed to buttress, or support, an upright row of books. It is placed on either end to prevent books from falling over, such as in a half-filled bookshelf. Bookends are both utilitarian and, often, decorative. They are common in libraries and in homes. Heavy bookends have been used for centuries; the simple sheet metal bookend was originally patented by William Stebbins Barnard, and uses the weight of the books themselves to make an anchor.