[kqr2]

In the US, the book's title has been changed to How to Bake Pi: An Edible Exploration of the Mathematics of Mathematics

Perhaps the publisher thought that "category theory" might not work well for American audiences?

http://smile.amazon.com/How-Bake-Pi-Exploration-Mathematics/...

[pavedwalden]

Thank you so much for pointing that out. I was having trouble finding the category theory book but finding the Pi one by the same author everywhere!