A beautiful pop-up book that is also a playful chase for children Between the covers of That’s My Hat! lies a pop-up city that is full of surprises. The adventure unfolds in three dimensions with the turn of each page: a blue hat blows away with the wind, only to be stolen by a mischievous monkey. Readers must follow the monkey as he scampers through a library, a bakery, a zoo, and other familiar places, transformed in this playfully illustrated, interactive world.