1. The spine of a new hardcover book can be stiff and might crack if it is forced open. To condition the spine, remove the dust cover and stand the book vertically on a hard surface with the spine down. Holding the pages upright, let the covers fall open. Then release the pages in 1/4-inch batches on alternating sides, pressing the pages gently as they fall. Continue until you get to the center of the book. Never force a book to open — if it doesn't open all the way, cradle the spine at an angle.
2. Always store books upright or flat, keeping similarly sized books together. Never lean them at an angle or vertically on their spine or pages. Don't pack books too tightly on the shelves or they may crack or become scratched if they are pulled out too roughly. To properly remove a book from the shelf, push in the two books next to it and grasp the book by either edge of the spine. Don't pull it from the top of the spine.
3. Don't store books too close to a heater, in direct sunlight or in damp places where they could become mildewed. If your books do mildew, try rubbing the mildew with a very dry cloth and leaving the book open in the sunlight for about 45 minutes (but not for too long or the book may start to fade). If the book is very valuable, take it to a specialist in book conservation before trying to clean it yourself.
4. When you dust your books, make sure to dust from the spine outward so that the dirt doesn't settle in the pocket behind the spine.
5. Handle books with clean, dry hands. Oils, perspiration, dirt and food residue can cause a lot of damage.
Found at Apartment Therapy