"Little boxes on the hillside, little boxes made of ticky-tacky. Little boxes on the hillside, little boxes all the same."

Millions of words have been published in the past half-century denouncing suburban sprawl, but it's doubtful that any have had the impact of those written by Malvina Reynolds in 1962 about tract housing in Daly City, California, and made famous by a Pete Seeger recording three years later. To a vast cohort of baby boomers, that song summed up everything wrong with suburban life: ugly little houses, robotic conformity, intellectual sterility, smug WASPy social isolation.

Reynolds died in 1978, but it's fair to say that she would be surprised by the altered image of the town she loved to hate. Daly City's residential population is now a pastiche, with Asian restaurants and a Filipino music scene. Some of the work of William Doelger, the community's architect and developer, is being considered for historic landmark status. Multi-color reproductions of Doelger's hillside boxes, painted by the San Francisco artist Warner Williams, are on display in some of the Bay Area's prestigious galleries and museums.

Of course, some people still find Daly City dull, but that isn't the point. The point is that the conventional wisdom about suburbs and sprawl can change dramatically over time. The row houses that sprouted up in South London in the late Victorian period and then again in the 1920s were routinely derided by social critics as vulgar and demeaning. Today, they are valued as prime examples of graceful, sensible urban design.

Daly City and South London are among the dozens of real-world examples cited by Robert Bruegmann, the University of Illinois art historian, in his almost compulsively contrarian new book "Sprawl."

Bruegmann shows that while we talk about sprawl all the time, we almost never define what we mean by it, and we revise our notions about it from one decade to the next. "Most urban change," he writes, "no matter how wrenching for one generation, tends to be the accepted norm of the next and the cherished heritage of the one after that."

But while the icons that stand for sprawl may be subject to change, Bruegmann believes that the phenomenon itself derives from a fixed element of human nature: the desire to spread out and settle one's family in larger spaces as soon as this becomes feasible. In other words, the low-density residential development that most of us currently recognize as sprawl wasn't created by greedy developers, or incompetent urban planners, or misguided federal policy, or even by the emergence of an automobile culture. It reflects an easily documented historic tendency for people, given the financial and geographical chance, to choose lower densities over higher ones.

Sprawl, Bruegmann says, "is the preferred settlement pattern everywhere in the world where there is a certain measure of affluence and where citizens have some choice in how they live." The row houses of South London offered more living space a century ago than the tenements of the East End; the boxes of Daly City were roomier than the apartments of inner-city San Francisco. And that's the same reason people are currently buying five-bedroom McMansions in the exurbs of Houston, Las Vegas and Phoenix.

Having declared sprawl to be all but universal, Bruegmann seems to be only a step away from defending it as a good thing. And by and large, he does. He is convinced that the American exodus to the suburbs in the late 20th century afforded millions of people a life that was unavailable to them in cities--and that was in no sense ruined by social conformity, architectural ugliness or too many hours spent commuting in cars.

Even if you despise sprawl, Bruegmann insists, it's far from clear that the problem is currently getting worse. In fact, if you look at metropolitan areas as a whole, they became denser in the past decade, not more sprawling. For most of them, the rate of decentralization was much higher during the first big wave of suburbanization, in the 1950s and '60s. A quarter of the houses currently being built in Chicago are row houses. Los Angeles, which is America's most densely populated area, continues to fill in and get denser.

About the only places in the country where the density level is actually declining right now are smaller and newer metropolitan areas. But as Bruegmann is quick to point out, it's not in those cities--the Little Rocks and Lubbocks--that the issue of sprawl is being discussed most intensely. It's in places such as Chicago, Cleveland and Kansas City. And there, he insists, the problem peaked a long time ago. "There is little evidence," he says, "that sprawl is accelerating, and considerable evidence that the opposite is occurring."

If this were as far as Bruegmann went, there wouldn't be much reason to write about his book. He could be dismissed as another strident anti-urban populist, out to defend the culture of gas grills, riding mowers and SUVs from the insults of an arrogant urban elite. There's plenty of that rhetoric floating around--in the blogosphere, on talk radio and in the pamphlets of the libertarian think tanks.

But this is where Bruegmann throws us a fascinating curve. He doesn't hate cities at all: He's a passionate urbanist. He calls cities "the grandest and most marvelous work of mankind." He doesn't live in the suburbs but in a townhouse on Chicago's Near North Side. He just thinks that the prevailing obsession with sprawl and suburbia is a distraction from the important task of urban revival.

In fact, Bruegmann believes that sprawl has been good for downtowns and inner cities. When traditional downtown functions relocated to the suburbs (not just housing but manufacturing, warehousing and even some retail business), the opportunity arose to rebuild the urban center around a new functional core--as a hub of entertainment and leisure and a residential magnet for singles, high-income couples and older people eager to sample a new form of urban life. "The stage was set," Bruegmann writes, "for a remarkable revival... While central cities have traded on their 'traditional' character, much of what is most attractive about them is the fact that so many of the things that once defined them have disappeared."

This is carrying the concept of creative destruction a bit further than I'm comfortable with. It's certainly true that deindustrialization of any downtown presents some opportunities. It frees up loft living space, for example, which has been the salvation of much of Lower Manhattan and a whole swath of neighborhoods surrounding the Loop in Chicago. But for every inner-city district that has emptied out and retooled, many more have emptied out and are waiting desperately for the revival to begin. Abandonment is an awfully high price to pay for the chance to start over. I wouldn't expect the leadership of Detroit or St. Louis to find Bruegmann's long view of urban history very consoling.

But in a larger sense, he makes a valid point. So much of the debate about urbanism and sprawl starts from the assumption that development is a zero-sum game and that decisions about where to live or where to locate a business are moral choices. To many self-described urbanists, each McMansion on the fringes of any metropolitan area represents one more insult to the principles of civilized community life. If people had any sense, they wouldn't live that way. If governments had any sense, they'd use their zoning power to make those monstrosities harder to build.

I have to confess to some emotional sympathy with that point of view. I find big McMansions on undersized plots of exurban land to be pretty appalling myself. I don't like it when a major employer leaves downtown, even though I understand the Bruegmann doctrine that something valuable may eventually come along to take its place. I don't support spending large amounts of public money on new suburban freeways. (Bruegmann doubts that the freeways themselves create congestion.)

And yet, I think that on the most important issues, he's right. Malvina Reynolds and Pete Seeger notwithstanding, we can't get rid of the worst of modern suburbia by insulting the people who live there. In fact, we can't get rid of it no matter what we do. It's there, it will remain, and more of it will be built. Bruegmann is correct: Sprawl is largely a force of history and geography and not primarily a consequence of any policy of government or any conspiracy by developers. Different policies might have altered the suburban landscape in modest ways over the past 50 years, but they couldn't have reversed them.

What we can do, many decades after the fact, is work to ensure that real choices exist for those who want to fashion a new form of urban life in the new century. That means public support for central-city residential living, investment in modern public transportation, and sensible zoning that allows experiments and supports developers willing to take risks. If we do those things, I'm reasonably sure that the new generation of urban-dwellers will show up. They are already showing up. Bruegmann is right about that. And we don't need to expend as much energy as we currently expend denouncing sprawl and wishing it didn't exist. In his words, "there is room for both Houston and Portland in a country as large as the United States." Bruegmann argues that sprawl is largely a force of history and geography and not primarily a consequence of any policy of government or any conspiracy by developers.