This book represents the second of two reading epiphanies I’ve had this year (the first was The Omnivore’s Dilemma). I pulled this book from the shelf at the library looking for a good follow-up to The Mathematical Experience. That book pulled the carpet out from under my mathematical education, and much of my personal philosophy in the process. It was a vivid illustration of my human longing for certainty, and my willingness to accept ideas without evidence in order to lay claim to that certainty. I clung for most of my life to an idea of mathematics as my bedrock, undeniable and pure, yet I had never closely examined that bedrock. When at last I forced myself to examine it critically, I saw there was no bedrock there at all, and the entire edifice collapsed. The false bedrock was the idea that there are basic objective truths that exist independent of humanity from which all of mathematics can be derived. Yet the more I tried to identify these foundational truths, the more convoluted and twisted they became, until I finally found myself unable to accept their reality. To my great wonder and joy, the authors of this book, with great clarity and care, gathered up the leftover bits and pieces of the edifice and rebuilt it before my eyes on an entirely different foundation: my own human experience. I’m convinced that I’ve witnessed a revolution that will probably not fully take hold of mathematics for another generation. The central principal that mathematics arises naturally from human cognition, and has no mystical existence in the fabric of the universe apart from us, will be unacceptable to many. For me, it is a gift to be able to relate to mathematics in terms I can truly have faith in – my own experiences. The idea goes well beyond mathematics and is changing the way I relate to all of my dearly held conceptual constructions. I feel privileged to have discovered it.