The San Diego Public Library's Wangenheim Collection contains a large portfolio of fore-edge paintings. These are images that have been painted onto the edges of a book (usually the edge opposite the spine). Sometimes the painting is visible when the book is closed. Sometimes the image is visible only when the pages are fanned. There are even books with double fore-edge paintings--fanned one way, the fore-edge displays one image; fanned the other way, the fore-edge shows an entirely different image.