220 million Americans crowd together in the 3% of the country that is urban. 35 million people live in the vast metropolis of Tokyo, the most productive urban area in the world. The central city of Mumbai alone has 12 million people, and Shanghai almost as many. We choose to live cheek by
jowl, in a planet with vast amounts of space. Yet despite all of the land available to us, we choose to live in proximity to cities. Using economics to understand...