In September 2000, when architectural historian Caroline Zaleski first came upon the modernist 1938 A. Conger Goodyear house in Old Westbury, N.Y., it was among faux-colonial red brick mansions, slated to be demolished to make room for one more.

Zaleski was a 52-year-old mother of two, fresh out of Columbia University's Graduate School of Architecture, Planning and Preservation. She had embarked on a survey of architecturally significant buildings on Long Island, dating from 1930 to 1980.

A fellow preservationist told her the Goodyear house, built about 30 miles east of Manhattan for the first president of the Museum of Modern Art, might be worth including in her study.

She found the concrete and brick structure, with a flat roof overhanging floor-to-ceiling windows, was being used as a construction shed. "It was covered in vines and filled with sandbags," she said.

The house's owner, Wheatley Construction Co., said it planned to tear it down. Zaleski began a successful collaboration to save what the World Monuments Fund today calls one of the most important modernist houses in the northeastern United States built before World War II.

This summer, Troy Halterman, proprietor of a luxury Soho retailer of European modern furniture called Troy, bought the house for an undisclosed sum. It came with an "easement" prohibiting him and the next owners from making substantial changes to the architectural features inside or out.

The purchase marks a victory for preservationists such as the World Monuments Fund, which helped acquire the house in December 2001 for $2.1 million. The preservation group said it earned a small profit from the sale, although not enough to cover restoration and other costs.

"The sale is a real save for modern architecture," said Henry Ng, executive vice president of the World Monuments Fund.

The sale also illustrates a revival of interest in mid-20th- century modernist architecture, which features right angles, natural light and open spaces. The resurgence has received the most attention in California, where devotees include fashion designer Tom Ford and actress Kelly Lynch.

"The generation of thirty- and forty-somethings is very keen on the mid-century modernist aesthetic," said Frances Anderton, host of "DnA: Design & Architecture" on KCRW, a Santa Monica, Calif., public radio station. "People are nostalgic for the era of their parents."

Anson Conger Goodyear, born in Buffalo in 1877, was an atypical champion of adventurous art and architecture. He was a lumber and railroad tycoon and treasurer of New York State's Republican Party.

While working with Edward Durrell Stone on the design for the Museum of Modern Art's first permanent home, on West 53rd Street, he commissioned Stone to build his country house.

Stone had visited Mies van der Rohe's Barcelona Pavilion and got to know Frank Lloyd Wright. Their influence is evident in the house, which has a large, central gallery space and a facade that is 70 percent glass.

Goodyear died in 1964. In the late 1970s, the New York Institute of Technology acquired the house, which sat on about 80 acres. Two decades later, the school sold the entire parcel for development to Wheatley Construction, which built houses on the property. (Wheatley employees who were involved could not be reached for comment.)

The Goodyear house was largely forgotten, even in architectural circles, by the time Zaleski happened upon it. To document its significance, at the Esto archive in Mamaroneck, N.Y., she found photographs taken in 1940 by Ezra Stoller, an architectural photographer who died last year at 89. Photos showed the house filled with art by Pablo Picasso, Paul Gauguin and others.

"They allowed the history of the house to come alive," she said.

She also found a 1957 letter from Stone, who had helped design Radio City Music Hall, the John F. Kennedy Center for the Performing Arts in Washington and 2 Columbus Circle. (The white marble facade of that nine-story building is slated to be dramatically altered by the Museum of Arts and Design, unless a band of preservationists prevail.)

Stone's letter was to Goodyear. "Your house is my best work to-date," he wrote.

While Zaleski researched the house's provenance, Wheatley Construction told her it planned to replace it with a new house that the company thought was more marketable. Zaleski persuaded the World Monuments Fund to add it to its annual list of the world's 100 most endangered sites. Lawyers for preservationists won a court order delaying demolition.

On Oct. 15, 2001, the New York Times published an article about the house that caught the attention of artist Frank Stella. He helped arrange a loan from the Barnett Newman Foundation, named after the artist who died in 1970. The World Monuments Fund and the Society for the Preservation of Long Island Antiquities, which employs Zaleski, used the money to buy the house.

The house would not resell for years, partly because Old Westbury is not a top market for second homes. "We often said, if the house were in East Hampton or Bridgehampton, it would have been snapped up," the monument fund's Henry Ng said.

Halterman, 41, a single father of two, grew up in a modernist house outside Salt Lake City. A former hair stylist on magazine photo shoots, he lives on the Upper East Side and has been searching for another home outside Manhattan.

"I told the broker I was looking for a modernist house, preferably from a notable architect," he said in an interview in the basement of his store, sitting at a white Formica table that sells for $2,568. "I didn't get a lot of calls. I was surprised to find a lot of the great houses from the 1950s had been torn down."

A Prudential Douglas Elliman broker showed the 5,000-square-foot, four-bedroom Goodyear home to Halterman, whose furniture clients include actor Richard Gere and model Christy Turlington.

"It's beautifully proportioned," he said. "Whether it's clothes or hairstyles or anything, I always prefer simplicity."

Halterman plans to move in shortly, after making repairs, upgrading the kitchen, and furnishing it. Nestled on five overgrown, bucolic acres, the house is bright with natural light but musty. Halterman hasn't decided whether it will be a primary or weekend residence.

Zaleski is finishing her survey of Long Island buildings. "You can bring attention to endangered buildings and get them saved," she said. "Some people say, 'It was a rich man's house, so who cares?' Preservation has to run the gamut."