Möbius shelves can be found in the Library of Unseen University. A Möbius strip has only one side, and the Möbius shelves are presumably the same. Exactly how you obtain books from a Möbius shelf isn't clear, nor how many books they contain. Since a Möbius strip has only one surface, a Möbius shelf would have the advantage of not wasting shelf space on a "off-side."
The name Möbius is named for August Ferdinard Möbius.