Abstract: A one piece folding blank foldable to form a book end having side walls and a base of triangular form, the planes and side walls and base being normal to each other. The blank comprises three rigid planes of similar right triangular shape. Two panels are joined to a central panel at fold lines consisting of flexible webs along non-hypotenuse sides. Cooperating and interlocking means are provided on the non-hypotenuse sides of the outer panels, the interlocking means releasably mating in the plane of one of the outer panels to secure the panels in position and form the book end when the panels are folded to positions normal to each other. When so folded, a pair of these blanks form a pair of book ends with base and side walls. The side walls are adapted to rest against the side and front or back portions of a series of books to stabilize them in upright position. Such book ends provide a neat and attractive means to display books in a multitude of different manners.