One of my aunts used to work for Doubleday, and the employees could buy "error" books at a substantial discount (or maybe they were free). I got a lot of children's books that way.
Here is the excerpt from Frank Colletti's (@Treashunt )book talking about inverted bindings if anyone is interested;
Nothing special, really. I've got one that's a 360° rotation. Should be worth double what a 180° rotation is worth.
Yeah, well I've got one with a 36,000,000° rotation! And several coins from the same year with matching rotations!
With a 180* rotation you just turn the book upside down but with a 360* rotation you’d have to do a cartwheel to be in the correct position.