Sublime

what do I say? That the internet is to the USA what the Americas once were to the UK—a frontier territory, where all the action is. That just as the Western frontier once gave rise to an American pioneer class, the internet frontier has given rise to a global technology class. That this class is not defined by inherited wealth (many are born poor

functional urban areas or, in less technical language, metropolitan areas.

These data make a strong case that, as human social networks grow, they necessarily lead to systems that require fewer resources per person, and produce more per person. In other words, the benefits of scale for human groups have always been there.

In this sense, cities are an outstanding example of complex adaptive systems: collections of individual constituents (people, in this case) that interact in myriad ways, usually mediated by some sort of network.

Cities should have languished. They have, so often, been expected to languish. But they have stubbornly refused to accept their fate. Instead, they thrived, attaining a centrality in modernity they didn’t possess even in antiquity. This, Glaeser writes, is “the central paradox of the modern metropolis—proximity has become ever more valuable as the

we will analyze the properties of urban systems through the lens of the interaction flows between cities.