A view of Chicago from the air, only some of the buildings have been hyper-stretched so that they're very large indeed.

It took me a while to understand why an economist was exactly the right person to write this book. It’s not that economists are the only people who can understand certain busted aspects of how the government subsidizes places to live; lots of people think about that. Hardly a week goes by, for instance, when Matt Yglesias doesn’t mention the insanity of American land-use policy. Rather, it’s that economists are specially trained to spot cases when what we think we’re doing is exactly the opposite of what we’re actually doing. And they’re trained to look at that sort of reversal in the context of large groups of people.

Take, for instance, everyone’s desire to live in bucolic wilderness. Everyone heads out to be among the trees in, say, Long Island. (Read Caro’s [book: The Power Broker] to hear what Long Island was like before Robert Moses made it what we know and don’t really love.) Soon enough there are highways leading out to where everyone wants to go. Soon after that, Dunkin’ Donutses and Fuddruckerses form along the highways that cater to the automobiles that brought people to their bucolic paradise. And by this point Long Island is no longer bucolic. The end.

That’s a commonplace sort of observation in the crowds I travel in: those desiring suburban living, away from the grittiness of the city, destroy the thing they were chasing. Observations like it are lurking beneath most of [book: Triumph of the City], and at the start I found it a bit of a yawn for that reason. Surely everyone already knows this.

But everyone *doesn’t* already know this, and I don’t know many popular books that make the point. It would be better if everyone *did* know this. A harsher, more-direct way to put the point is that those who live in the supposedly dirty city among the asphalt and concrete are the real environmentalists; those driving their cars off into the hinterlands to find nature are thereby destroying it.

This sort of paradox of individual behavior leading to collective destruction is the stock-in-trade of economists, and Glaeser deploys many arguments of this sort. The most surprising, for me, was Glaeser’s observation that environmental-impact statements are flawed because they’re not wide-ranging enough: when a building gets rejected in temperate San Francisco Bay, whose residents drive relatively little and rarely need to use heating or air conditioning, that building will eventually get built — in a different, less-green city, like Vegas or Houston or Phoenix, that has more-flexible land-use policies. Which is to say that good regulation needs to focus not only on the immediate environmental devastation (or ruined lines of sight from nearby small buildings, say), but on the big economic picture. Rejecting a building because of its environmental impact may, again paradoxically, be worse for the global environment than allowing it.

The other main reason you want an economist to look at housing problems is that those problems are fundamentally about supply and demand. If you think it’s too expensive for a middle-class person to own a house in Boston (which it is), you need to increase the supply of houses. Raising supply, for a given level of demand, means lower prices. But cities like Boston and New York are basically full: there are no more parcels of land to build on. So the only option to increase supply is to build *up* rather than *out*. In many cases this will mean demolishing an old building that has some historical appeal for those around it, and replacing it with a taller building that houses more people. But as the decades have gone along, Glaeser tells us, regulation has made it harder and harder for cities to modify old neighborhoods. The inevitable outcome is that supply doesn’t increase as rapidly as demand, and housing prices rise. When housing prices rise, many people decide they’d rather live somewhere where they can own a bit of land without sacrificing their firstborn children. And the Sun Belt boom is born.

People *do* continue to move into Boston and New York City. The combined population of Middlesex and Suffolk counties in Massachusetts — containing two of the Commonwealth’s two most populous cities and many of Boston’s suburbs — rose by a healthy 4.7% from 2000 to 2009. People moved here despite the high home prices, because cities offer them something they can’t get anywhere else: dynamism and excitement that can only come from putting a lot of people near one another and watching the combustion that results.

That’s Glaeser’s central argument: that there is fundamentally no replacement for cities, because no other institution humanity has constructed is as good at harnessing our creative energies. The world continues to urbanize, and all indications are that the pace of urbanization will only increase as China and India move to their great cities. In many cases (think of Rio’s [foreign: favelas]) they crowd into slums, and that may look terrible to us, but they’re moving into seemingly terrible slums *because the rural lifestyle they’re leaving was so much worse*. People’s own behavior indicates that urban life, for all its gritty lack of charm, is humanity’s best hope for a better life.

When does people’s own behavior *not* reflect their natural evaluation of what’s best for them? When government policy shifts their choices in a different direction, and when the prices they pay for their choices don’t reflect the true social cost of those choices. Americans live in the suburbs, for instance, for some natural reasons and some less-natural ones. Among the natural ones: schools are often better in the suburbs, their kids have a bit of lawn to play on, and homes are cheaper. Among the less-natural ones: the government subsidizes the Interstate Highway System, and encourages (via the mortgage-interest deduction) homeownership over renting.

Plus the price we pay for gas doesn’t cover the damage we do when we belch smoke into the atmosphere. Glaeser tosses out some numbers toward the end of [book: Triumph of the City] suggesting that American gas taxes ($1 or so per gallon) don’t nearly cover the social cost of burning gasoline, while European taxes (averaging $2.30 per gallon) may be too high.

(I’d want to read the research backing this. A lot depends upon how you model the environmental cost of a pound of carbon. If the greenhouse effect’s response to an additional pound of atmospheric carbon is highly nonlinear — if we eventually cross a point of no return — then this would strongly encourage us to *stay away from that point*. If, instead, the response is very smooth — if increasing carbon by a little increases damage by a little — then that would seem to make policymaking somewhat easier. Or rather, would make the required policies less drastic.

We should add another important angle to this, namely how our policies should react in the face of our ignorance. What if our models of how the greenhouse effect responds to an additional pound of carbon are wrong? If the atmosphere is more fragile than our models predict, then undertaxing carbon is really, really bad. If the atmosphere is *less* fragile, on the other hand, is it really so bad to overtax carbon? This isn’t just technical noodling: if the point is to charge people the actual cost of the pollution they’re causing, you’d better figure out what “actual cost” means.

[book: Triumph of the City] doesn’t pursue this sort of direction. The book as it stands is about lightly exercising our intuitions about cities to lead us to surprising conclusions. It’s not about running off into the weeds with technical details. If you want those, the book is very well-footnoted.)

If anything, Glaeser is too conservative in his lambasting of American anti-urban policy. The true cost of gasoline includes the cost of invading foreign countries whenever our supply of oil is threatened. And surely those who buy and sell crude-oil futures know that the supply of Middle East oil is unlikely to drop so long as the U.S. government stands ready to secure it with guns. So a true accounting of the price of oil would include much of the cost of maintaining the U.S. military *even in peacetime*.

Glaeser doesn’t mention this sort of detail. It must be because he’s aiming his book at people quite unlike me — people who are starting from an anti-urbanist background. The main battleground he’s chronicling in [book: Triumph of the City] is urban v. rural rather than urban v. suburban. In part that’s to avoid charges of hypocrisy: to get better schools and a lawn, he and his wife and kids moved a few years back to MetroWest, while he continues to commute into Cambridge via Interstate 90 to work at Harvard.

That commute indicates probably the more important reason that Glaeser doesn’t hate suburbs: the suburb is still within reach of the city, and therefore makes it part of the engine of economic dynamism that he lauds. People are still near enough that they can sit down face to face (after a short drive, perhaps) and build the great works that cities produce. The point is human interaction, which is not available to nearly the same extent within rural areas.

What about the Internet, then? Doesn’t the Internet make physical proximity obsolete? This is clearly the major difficulty that Glaeser is going to encounter with his thesis, and I don’t think he really resolves it. He asserts that the Internet makes person-to-person interaction *more* valuable, and that certain work just needs a handshake and two people sitting together hashing something out. I certainly agree, but this doesn’t have the same rigorous economic grounding that he brings to the rest of his book.

The bulk of the book is organized around some axioms of economic thinking. Let people choose whatever they want to choose — if they want to live in suburbs, fine; if they want to live in cities, fine — but make them pay for their choices. Let the supply of housing rise to meet its demand. And bring some economic discipline to the way we educate our kids: let poor schools fail, let poor teachers lose their jobs, and let great teachers be paid well. With the market allowed to work the way it should, Glaeser has no doubt that cities will continue to be vibrant centers of innovation. If you’d like a rather breezy yet informative take on cities, [book: Triumph of the City] is a good use of a few hours of your time.