Doorway to a secret staircase library.
A Tardis bookshelf - because it's bigger on the inside.
Bookcase made from an old organ.
Ceiling bookshelf as seen on Apartment Therapy (via mouchoux on flickr).
Store your books in a "Bookman" shelf.
Rolling bookcase chair.
Murphy bed bookshelf. Brilliant! But how do the books stay on the shelves?
Inverted bookshelf - store your books UNDER the shelf!
Magazine chair (and other chair bookshelves at the Bookshelf blog).