A New York architectural firm was selected yesterday to design an underground exhibit center at the Vietnam Veterans Memorial that is to be one of the last projects built on the Mall.

Polshek Partnership Architects, selected from four finalists culled from a field of 39 entrants, was asked to design a building that would offer a one-of-a-kind educational experience yet not compete with the emotional impact of the memorial's iconic black wall of names.

The $40 million center, to include 10,000 to 12,000 square feet of exhibit space, is expected to take three to five years to construct. It will be built with private money, and cost estimates have quadrupled since it was proposed four years ago.

President Bush signed a bill authorizing its construction in November. The bill also banned future construction of memorials, monuments and interpretive centers not already approved.

The Vietnam Veterans Memorial Fund, the private group sponsoring the center, would not release details of the winning entry, saying it is only conceptual in scope. But Jan C. Scruggs, fund founder and president, described the ideas of the Polshek firm and its exhibition designer, Ralph Applebaum Associates of New York, as "brilliant."

"I wanted to do this very much," James S. Polshek, the firm's founding partner, said in a phone interview. "I've always seen architecture as a healing art, not just as a beautification art. If ever there was a project that has at its core the necessity for healing or reconciliation, this is it. And, by the way, never more so than today."

Polshek and Scruggs said the underground structure will be as much about landscaping as architecture. Polshek said he intends his design -- which will need approval by federal fine arts commissioners -- to show "respect for the memorial itself" and avoid any appearance of creating something "seen to be derived from the design of the memorial." He also will give priority to preserving the Mall's vistas and trees, calling it "one of America's great sacred spaces."

"It won't really compete with the Wall," Scruggs said of the center. "It will truly complement it."

Scruggs was among five jurors who made the selection after hearing presentations from the four finalists this week. Others included representatives of Ana Beha Architects of Boston; Architecture Research Office of New York; and Michael Graves & Associates of New York.

Maya Lin, architect of the memorial built in the late 1970s, was a special adviser to the jury. In a statement, she said the architect-designer team "will create an incredibly brilliant and respectful piece of architecture that will match something I'm really close to."

The center's exhibits will include many of the artifacts left at the wall as tributes to those who died in Vietnam. Retired Army Gen. Barry McCaffrey, a professor at the U.S. Military Academy at West Point who was awarded three Purple Hearts in Vietnam, will chair the exhibit selection committee, Scruggs said.

The Polshek firm is designing the layered steel and glass Newseum building at Sixth Street and Pennsylvania Avenue NW, which is scheduled to open in 2007, and the Clinton Presidential Center in Little Rock.

Its portfolio includes the Cultural Resources Center, a storage, research and ceremonial facility in Suitland for the Smithsonian's National Museum of the American Indian, as well as the Rose Center for Earth and Space, a dramatic glass cube attached to the American Museum of Natural History in New York.

The firm has collaborated several times with the Applebaum exhibit designers. Applebaum created the exhibits for the U.S. Holocaust Memorial Museum and is involved in the design of the new interpretive facilities at the U.S. Capitol visitors center as well as the Clinton presidential library.

The firm of James S. Polshek, left, will design the exhibit center, with collaboration from Ralph Applebaum, whose designers created exhibits for the Holocaust museum.