Bowery Dreams.(New Museum of Contemporary Art)

In the past few decades, American museums have discovered an easy way to get themselves noticed: put up a building by an international architect who hasn't built much in this country before. Too often, though, these exciting debuts go nowhere. Mario Botta's San Francisco Museum of Modern Art, Josef Paul Kleihues's Chicago Museum of Contemporary Art, and James Stirling's Sackler Museum, in Cambridge, all failed to earn their creators any more American museum commissions.

In 2002, when the New Museum of Contemporary Art in New York began to plan for a new building on the Bowery, east of its previous location, in SoHo, it decided to limit the search to younger architects who had not built anything in New York. "We thought we should be consistent with our mission of supporting new art," Lisa Phillips, the director, told me. The search led the museum to SANAA, a twelve-year-old firm in Tokyo, whose principals, Kazuyo Sejima and Ryue Nishizawa, are known for buildings of almost diaphanous lightness. When the museum hired them, Sejima and Nishizawa had just one American commission, the Glass Pavilion, at the Toledo Museum of Art, an eye-catching structure of curving glass walls, which opened last year. Their best-known work includes a low-slung circular art gallery with no clear front or back, in Kanazawa, Japan, and a design school in Essen, Germany, that is a concrete cube a hundred feet high, punctuated, seemingly at random, with windows of assorted sizes.

SANAA's refined style might seem odd on the Bowery, one of the grittiest streets in New York. The site, a former parking lot at the intersection with Prince Street, was framed by blocks of restaurant-supply stores, whose owners seemed to be the only property holders on the Lower East Side who showed no interest in selling out to condominium developers. But after two decades in SoHo the New Museum had seen both the upside and the downside of gentrification. Marcia Tucker established the museum in 1977--the day after she was fired from the Whitney for curating shows that it found too controversial--in order to focus on cutting-edge art. Yet as the museum grew larger it drifted from its radical beginnings, just as the Museum of Modern Art had done two generations before. The decision to move to the Bowery was perhaps a clever way of assuring its supporters that its agenda remains radical.

But things have changed since the New Museum purchased the lot, in 2002. There is now a Whole Foods nearby, several luxury condominiums within view of the museum's front door, and expensive shops, including a Ralph Lauren, amid the former tenements around the corner. The area hovers between a grungy past and an overpriced future. The New Museum may have left SoHo, but it is powerless to prevent SoHo from following it to the Bowery.

Sejima and Nishizawa have designed a building that is just right for this moment of the Bowery's existence. It is a pile of six boxes, stacked unevenly, like a child's blocks. Sometimes the blocks mount up in a pattern of setbacks like that of a traditional New York building; sometimes they jut out over open space in a way that suggests the architects had something more radical in mind. The building is original, but doesn't strain to reinvent the idea of a museum. Sejima and Nishizawa have a way of combining intensity with understatement.

What makes the museum unlike any other building in New York is its surface--corrugated-aluminum panels painted silvery gray, with an aluminum mesh suspended an inch and a half in front of them. The mesh is a standard industrial material but it gives the building the lightness of glass and the porosity of fabric. The visual signals this building sends--it is at once ...