"The best place for books is a cool, dry environment," says Jeffrey Rigby, a book conservator in Hudson, New York. "But usually you have to keep books where people are, so the next best thing is to avoid putting them where there are radical swings in temperature and humidity from day to day and from season to season." A room in which the temperature stays between 65 and 70 degrees and the relative humidity remains at 50 percent is fine, Rigby says. He also recommends keeping books away from large doses of direct light — sunlight and fluorescent light, especially, which cause deterioration and fading — and from the heat of radiators and fireplaces, which can make books brittle. Wood shelves — whether left raw, coated with polyurethane, or painted — pose no danger to regular books (if painting, choose a latex or oil-based semigloss for easier cleaning). However, you should line wood shelves on which you're going to place rare or fragile books with Mylar or plastic sheeting, and cover the books with polyester book jackets or acid-free and buffered paper wrappers. Rare books can also be stored in acid-free book boxes.

Dust can be abrasive, so it's important to clean books regularly. Dust with a clean cloth or soft brush, moving away from the spine and toward the front edge. You can also vacuum books, using the brush attachment or placing cheesecloth over the nozzle to reduce the suction. Damage to any precious volumes should be repaired by a book binder or a conservator (contact the American Institute for Conservation of Historic and Artistic Works, www.aic.stanford.edu).