An observer of the American scene in 1990 might have been forgiven for thinking that cities were in terminal decline. They had been hit in the postwar years by the automobile and the exodus to the suburbs; by air conditioning and migration to the Sun Belt; by crime, drugs, and white flight. To top it all off, there was the looming revolution in information technology that stood on the verge of abolishing distance and rendering the whole concept of massing huge pools of people obsolete.

Triumph of the City:
How Our Greatest Invention
Makes Us Richer, Smarter,
Greener, Healthier, and Happier

by Edward Glaeser
Penguin Press HC, 352 pp.

But it didnt happen. The great crime wave of the 1960s, 70s, and 80s eventually came and ebbed, and urban America started coming back. And though Sun Belt metropolises like Las Vegas, Houston, and Atlanta dont look like old-fashioned cities, theyre definitely citiescrowded places with centers and peripheriesand not just random blurs of people.

The turnaround did not reach all urban centers equally. Many great American cities were founded as clusters of manufacturing enterprises, and even though U.S. industrial output is higher than ever, trade and technology means that fewer and fewer people are needed to run Americas factories. The result has been continued decline for many manufacturing hubs, often to the point where upkeep of the basic urban infrastructure has become an intolerable burden and the best hope for improved quality of life is some form of planned shrinkage.

But many metropolitan areasSan Francisco, New York, Boston, Chicagoinitially envisioned as manufacturing or transportation hubs have become thriving centers of the information economy. Meanwhile, much of the Third World has experienced explosive economic growth and massive new waves of urbanization. In a world where instant, cheap, global communication is possible, more people than ever are packing themselves into big cities.

Explaining all this is the main task of Harvard economist Edward Glaesers new book, Triumph of the City. Organized as a series of chapters, each of which is meant to answer a single question (Whats good about slums? Why has sprawl spread?), the book offers a popular treatment of Glaesers main findings in urban economics. The result is a book thats more meandering, engaging, and entertaining than one thats trenchant and polemical, but a few key themes do emerge.

One is that cities provide economically useful interactions between skills, education, and the information revolution. Theres still no better communications technology than the face-to-face chat, which is why people generally work in offices and important decisions get made in meetings rather than email chains. Thus while new information technology has made it possible to work in splendid isolation from the Yukon Territory, in practice the main impact has been to spur growth in info-centric industries. These industries, in turn, rely on pools of skilled workers, and that means cities that create a virtuous circle in which employers are attracted by the large pool of potential employees and workers are drawn by the abundance of potential employers. A company needs to be located someplace where qualified personnel are already living in order to expand, and skilled workers benefit from living in places with multiple potential employers. Firms come to Bangalore for the engineers, Glaeser explains, and engineers come for the firmsand this is equally true of Silicon Valley and programmers, Washington, D.C., and political journalists, and Boston and medical research. Consequently, an edge in skilled labor can give a city an entrenched advantage. As the share of the population with college degrees increases by 10 percent, Glaeser finds, per capita gross metropolitan product rises by 22 percent.

In the American context, this interacts with the reality that poor public schools are often a major driver of out-migration to the suburbs. This is why, Glaeser notes, education policy is vital for urban success. Unfortunately, what Glaeser has to say in this regard tends to be a bit gliba breezy two-page brief for the standard reform playbook of charter schools and performance pay for teachers that will do nothing to convince skeptics, but may close some eyes to the books more substantive insights.

Those insights are at their most important on the subjects of poverty and real estate development. The large concentrations of squalor visible in the worlds major cities tend to cast these places in a bad light. Casual empiricism can make it seem that cities and urbanization cause poverty. The truth is the reverse: while rural poverty is often more picturesque than slum dwelling, its considerably more severe. Cities attract the poor because theyre engines of economic opportunity. Glaesers research finds that in the United States, when you control for demographics, workers in metropolitan areas with big cities earn 30 percent more than workers who arent in metropolitan areas, and the effect is even bigger in poor countries. Higher living costs partially offset these increased earnings, but they also reflect higher wages driven by the higher productivity facilitated by dense cities greater scope for specialization and information transfer. And, crucially for the future of the planet, city dwellers smaller homes and shorter, less car-focused commutes lead to dramatically lower carbon footprints. Achieving progressive goals of economic mobility and ecological sustainability, in other words, requires bigger, denser cities.

And this, Glaeser is keen to argue, requires giving up on some sacred cows. He condemns the agrarian utopianism of those who sentimentalize rural living and fail to appreciate the environmental virtues of big cities, chiefly less driving and the greater energy efficiency of heating multifamily structures. He argues that conventional environmental impact reviews fail desperately by not considering the impact of not building new homes. Houston, he notes, has attained extremely rapid population growth largely because Houston-area authorities have chosen to allow people to build houses in the Houston area, attracting middle-class residents in search of affordable housing. Every time additional development in coastal California is blocked, the would-be inhabitants of the development dont vanishthey simply move to places like Houston, Phoenix, or Las Vegas, where sparser dwelling patterns and hotter weather then lead to higher carbon emissions. Excessive historic preservation laws have a similar impact, turning central cities into boutique areas that only the rich can afford. More broadly, Glaeser observes that over the past forty years, weve experienced a little-remarked revolution in property rights in America, shifting a paradigm where people could essentially do what they wanted with their own property to a system where neighbors have enormous power to restrict growth and change. This, combined with pervasive pro-sprawl bias in federal housing and transportation policy, is a disaster for our economy and our environment.

But while Glaesers overall thesis is compelling, his affection for tweaking liberals sometimes leads to questionable emphasis. Yes, historic preservation and environmental impact review can limit density. But they can also make cities more appealing and livable, and hence more attractive to employers and highly educated workers, which leads to economic growth that benefits everyone. Moreover, preservation and environmental review in Americas central cities are hardly the main barriers to a denser country. Consider the D.C. area. To accommodate 600,000 additional people, the city of Washington, D.C., which is relatively small and already fairly compact, would need more than 4,300 more people per square mile, nearly a 50 percent increase in population density. By contrast, increasing the population density of adjoining Montgomery County, Maryland, up to the level of nearby Fairfax County, Virginia, would achieve the same thing. Suburban jurisdictions are big, and small differences in policy there can have a huge impact.

Glaesers emphasis on preservation and environmental reviews also distracts attention from other measures that, in the vast majority of jurisdictions, are far more important in keeping densities low: minimum lot occupancy rules, bans on multifamily structures, mandated parking minimums, and so on all conspire to prevent efficient use of space. The argument that curtailing density is bad for the economy and the environment and tends to turn our most desirable locations into exclusive preserves of the rich may be persuasive; what is less clear is whether its in any particular jurisdictions interest to change.

Glaeser bemoans the fact that central Paris has become unaffordable to the nonwealthy, but its a situation that suits the wealthy just fine. Similarly, incumbent property owners in Manhattanespecially those who bought low in the late 1970s or early 80sbenefit mightily from curbs on new construction. Glaeser seems at times to assume that failure to understand the issues properly is leading to bad policy, but the real issue seems to me more likely to be bad incentives and bad institutions. A mayor might well come away from this book more convinced than ever that regulatory measures that limit density and make his town unaffordable to the poor are good ideas. Suburbs, in particular, do well by offloading the challenge of poverty to adjacent areas. A central challenge is for federal policymakers to do a better job of using the leverage at their disposalprimarily moneyto drive change. Washington is awash in proposals for one or another form of a national infrastructure bank, and the federal transportation bill is overdue for reauthorization. Either would be a good opportunity to tie federal money to local policy shifts that facilitate both density and affordability.

If you are interested in purchasing this book, we have included a link for your convenience.

Matthew Yglesias

Matthew Yglesias is a fellow at the Center for American Progress Action Fund.