Some people like books, others love them. My boyfriend happens to love his books. He doesn't have any rare antique collectables worth hundreds of dollars, but each one of his books means something special to him. He reads his favorite ones over and over and will quickly recommend a book for any occasion. He has stories for long flights, a day at the beach or when you are home sick. It makes him nervous to lend any of his books out to friends (even me). He can't see where they are left, how they are read or know when, if ever, he will see his beloved book again.
I admire someone who respects the art of literature so deeply. If you love your books, you probably care for them quite well. So instead of enlightening those who already know the proper way to handle books, this is for all you renegade book readers.
Dust is not a book's friend. The top edge of your books should be dusted every couple of weeks and vacuumed once a month. If you'd like to protect your books entirely from dust, they can be kept in a cabinet with glass doors or stored in giant plastic containers and bins.
Sunlight can bleach and weaken cloth bindings. Dust jackets are a great way to keep the bindings from fading or staining. If you put a book cover on before you lend a book out, your borrower is more apt to use the flap as a bookmark rather than then dreaded "dog ear" corner fold.
Silverfish and other insects eat the glue used to bind books. Aside from saving your books, try to eliminate these bugs from your home. Silverfish may be eliminated with a sweetened mixture of 1-3/4 cups wheat flour or oatmeal ground to flour, 1/4 teaspoon sodium fluoride (available in drug stores), 1/2 teaspoon granulated sugar, and 1/4 teaspoon salt; once mixed, the powder can be placed in shallow cardboard boxes loosely covered with crumpled sheets of paper. The mixture is ample for several good sized rooms, and the boxes may be placed in areas where silverfish are known to occur.
Arrange bookshelves so that all the books are tight enough to remain standing upright. You don't want to fight to pull the book out, but you don't want the spine supporting the entire weight of the book. Doing this will eventually cause the pages to become loose in the binding and fall out.
Handle books carefully. Never pull a book off the shelf by the top of the spine. Grasp it from both sides and slowly pull it out straight.
When you open a book for the first time, don't let the book fall open to the middle: the cracking you hear is the spine weakening and separating.
When you read or hold a book put your thumbs anywhere but on the corner of the book page (similar to looking at photographs). Every time a fingerprint is left on book page you create a chemical process that destroys the paper.
Try to read a book on a desk or table, or, if you must hold it, cradle it by the spine.
Torn pages will only get worse. Scotch tape is a fine way to solve the problem, but for keepsake books use Filmoplast P, a clear, ultra-thin acid-free paper repair tape. 
