Flash (and I believe Pledge) make wonderful dusters that really pick up the dust and dirt - and dont just redstribute it like feather dusters do. Just take them and wipe the top of each book - which is where the majority of the dust collects

The day before you're going to clean the bookshelves, turn a blow-dryer on "high" and wave it across the tops of all your books. Let the dust settle for a day, then pull the books off the shelves and dust the shelves.

Try vacuuming the books and shelves, it saves having to remove them all and keeps the dust from spreading around the room.

A soft paintbrush works a treat on bookshelves and books. Doesn't damage books and cleans the bookshelf without having to remove the books.

I find a feather duster works perfectly, have a piece of kitchen towel in the other hand and after a couple of strokes of the feather duster just wipe the dust off in to the kitchen towel and continue with dusting. The feather duster is so light that you can work around book, picture frames and ornaments.