To protect books from dust, crisp lengths of linen can be hung from shelves. The technique, used in old Swedish libraries, also gives a neat appearance to uneven volumes. To make, measure the length of the shelf, and the distance from the shelf above to the top of the shortest book. Add 1 inch to all sides; cut prewashed linen to this size. Hem bottom and sides by 1 inch. Sew 1-inch-wide twill tape to top edge. Fasten to underside of shelf every 6 inches with upholsterers' tacks or a strip of Velcro.