Is the city becoming obsolete? Many social observers believe that it is. In their view, improved information and transportation technology has deprived urban density of its raison d?étre. It is taking different connotations.They also argue that many cities have caused themselves irreparable damage by pursuing policies that have attracted the poor and repelled the rich. The combination of foolish policies and technological change, they say, has doomed the city.

Ongoing technological developments do indeed have massive implications for urban form. It is also true that many cities have followed policies that, in hindsight, appear unwise. Without question some cities are in deep decline. Some may not recover. But the turn of the new millennium does not presage the end of a ten-thousand-year pattern of increasing urbanization.

Are cities here to stay? Envisioning their future requires understanding their functions. Ultimately, it’s true that the future of cities depends on the demand for urban density. And the demand for density depends on what density does.

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