Across the street from my house, our local public school is getting some improvements. The playing field that slopes down toward the street, turning into rivers of mud every spring, at last has been shored up with a concrete retaining wall. The playing field is finally level and newly green.

At first I was worried about the ugly five-foot wall, but they've even laid some handsome stonework over the concrete. And this morning I noticed that, overnight, some attractive plantings had appeared in front of the stone wall.

This is, of course, courtesy of the Brookline taxpayers, of whom I am one. I no longer have school-age kids, but how marvelous to see the public sector doing something thoughtfully and well.

My relatively affluent town can certainly afford this. But for 20 years, ever since local taxpayers in rich towns and poor ones alike began revolting against property taxes driven skyward by inflation, small public amenities like these have been deferred and denied. We've gotten used to the idea that things public should be vaguely shabby.

Nationally, too, this has been a dry season for public improvements. The idea has been rampant that only the private sector contributes to our individual and collective well-being, while the public sector is a drain. Civilian public investment is now at the lowest share of gross domestic product in three decades.

But surely this view is short-sighted. Our public spaces and public improvements are part of what makes our economy efficient and our common life attractive.

Here in greater Boston, the "Big Dig" is the largest public works project in America. One of the nation's ugliest elevated six-lane highways is being moved underground, creating new prime downtown development land and parkland and opening up vistas to Boston Harbor. Though completion is years away, one notorious highway bottleneck already has been cleared, cutting my own commute in half. For all of the chaos, the project is a wonder.

On a recent visit to Chicago, I noticed a sparkling array of public improvements courtesy of the Daley administration. Mayor Daley, who is fond of ornate ironwork and flower boxes, has showered the downtown with both. He took a fair amount of grief for spending public dollars on what some considered frills, but these amenities are good for business, and they energize the city's self-confidence.

His honor also initiated a new era of public art, most recently in the form of hundreds of whimsical statues of cows, which delighted locals and tourists alike. Happily, few of Chicago's public improvements are sponsored by this or that corporation. They are genuinely public and proud of it.

In New York, visiting a friend in Brooklyn Heights, I was introduced to one of the city's small marvels, the Brooklyn Heights Promenade. This is a pedestrian walkway about eight blocks long with a glorious view of New York harbor from the Brooklyn side. The promenade has a feeling of timelessness, but it dates only to the 1950s, when New York's master planner, Robert Moses, came up with the idea of covering an ugly stretch of expressway with something functional, small and beautiful.

Soon, an underused area of warehouses and parking lots below the promenade will become another public park. The development of the park is being carried out in careful consultation with community residents.

The 19th century was the golden age of public planning for public spaces. It was the era when our splendid parks were laid out and saved from private land-grabbing. In the late 20th century, many of these functions have been turned over to private developers.

Now, ironically, there is a backlash against "sprawl." But sprawl is another word for the absence of public planning and public investment. If we want our metropolitan areas to use space more efficiently so development is more compact while open spaces stay open, some public planning process is required. It invariably will interfere with some scheme of some private developer, and it invariably will require public resources. To date, only one large metropolitan area, Portland, Ore., has reclaimed enough public authority to have a truly effective anti-sprawl program.

Some of our downtowns already are looking brighter, but nationally an immense backlog of public parks, schools, subways and squares is in need of refurbishment. Paradoxically, a period of unprecedented private affluence is exactly the right time to reclaim what is necessarily public.

Robert Kuttner is co-editor of The American Prospect.