Like the Umbra Conceal Bookshelf? This is a similar idea but it's been around a little longer. It's a long, think strip of metal with a projectile-like, grippy surface. you just shove your books onto the Sticklebook and they stay there!

You can mount it vertically or horizontally. If you fill up the whole "shelf", it looks like a row of books neatly floating in mid-air.

Another "floating book" type of bookshelf. A cool find. (via joox)