Did you mean Paul Lockhart? His book, "Measurement" is also good. He starts with some simple concepts, like length, and goes on to develop Geometry and then Calculus while encouraging the reader to consider various questions along the way.

Yes, Lockhart! This is why you shouldn’t post with jet lag.

He uses a similar approach in “Arithmatic”. He begins the book by describing different base number systems used throughout human history (the way different civilizations did “counting”). He does that in order to argue that a number itself shouldn’t be confused with its representation.

I might check out “Measurement” next! Thanks for the recommendation.