Magic has entered our world. In the pockets of many Americans today are thin black slabs that, somehow, understand and anticipate our desires. Linked to the digital cloud and satellites beyond, churning through personal data, these machines listen and assist, decoding our language, viewing and labeling reality with their cameras. This summer, as I walked to an appointment at the University of Toronto, stepping out of my downtown hotel into brisk hints of fall, my phone already had directions at hand. I asked where to find coffee on the way. It told me. What did the machine know? How did it learn? A gap broader than any we’ve known has opened between our use of technology and our understanding of it. How did the machine work? As I would discover, no one could say for certain. But as I walked with my coffee, I was on the way to meet the man most qualified to bridge the gap between what the machine knows and what you know.