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.

You could carry this one step further by simply laying a cloth over the tops of the books, behind the suspended linen, for added dust catching. I'm a librarian, and didn't know this about "old Swedish libraries," so I find it especially charming and interesting.
Thanks for this so simple and practical idea. I always thought the best way to protect them from dust was to enclose them in glass.Thanks again.
I like to read, so I have so many books on the bookshelf. However, it is very hard for me to keep them from dust. For me, this is a fantastic idea. Thank you for sharing. I have to try this. Good luck to me!