The former Department of Education building in downtown Brooklyn, which Mayor Giuliani once famously declared he would like to see blown up, is being put to productive use.

110 Livingston, for generations synonymous with the Byzantine bureaucracy of the public school system, has over the past four years undergone conversion into 300 luxury residential apartments designed by the architectural firm Beyer Blinder Belle. Residents are now beginning to move in.

The architectural firm McKim, Mead, and White built the original structure in 1926 as a headquarters for the Benevolent and Protective Order of Elks. It had 200 dormitory rooms, a ballroom, bowling alleys, Turkish baths, and a swimming pool. The Board of Education took over in 1939, converting the Beaux-Arts structure into a warren of offices, dingy hallways, and a “rubber room” for teachers on disciplinary suspension.

“It got to the point where everything that was wrong with the Board of Education was tied to the name ‘110 Livingston,'” an architectural historian and the author of “Luxury Apartment Houses of Manhattan,” Andrew Alpern, said. “People of a certain age would have a mental problem with living there.”

The Bloomberg administration sold the building to Two Trees in 2003 for $45 million.

“It’s a New York City address that has had significance for decades, and has its own branding,” Craig M. Notte, a Fort Green-based real estate attorney who purchased an apartment in the building, said. “It brings together the old and the new in an underrecognized part of Brooklyn.”

The architects kept the classical, solid stone façade, enlarging the original masonry windows and adding a four-story zinc and iron crown.

“It’s about taking fragments of the old and fragments of the new and creating a new life in the city,” Michael Wetstone, the lead architect on the project, said. “We needed to make the rhythm and details of the new sympathize and harmonize with the rhythm and details of the old. We tried to not have it be too flat, and keep the richness and texture of the original.”

The building has been divided into studios, and one-, two- ,and three-bedroom apartments ranging in price between $300,000 and $1.5 million. Twenty-six private 300-square-foot rooftop cabanas, part of the four-floor Beyer Blinder Belle–designed addition, can also be purchased for between $100,000 and $200,000. A 225-car underground garage is being added.

Of the 300 units, 270 have already been sold, due in part to an unorthodox marketing campaign that includes 1,500 subway advertisements, a Web site featuring video of buyers’ testimonials, and a 110Livingston. net blog.

“People think that the consumer is coming here just because it costs less than Manhattan,” Asher Abersera, who designed the marketing for the building’s management company, Two Trees Management, said. “But people don’t feel anymore like they are making a compromise by living in Brooklyn. They want to live in this immediate area. They are just looking for the right kind of product that fits the needs of their lifestyle and has class and finishes that couldn’t be found in other buildings.”

Two Trees was an early developer in the DUMBO area, helping to transform it into high-end residential neighborhood from an edgy arts neighborhood. Some are wondering if the developers are attempting the same kind of neighborhood conversion in the area around 110 Livingston. The building includes a 6,000-square-foot theater that will be rented out for free to a nonprofit arts group, an effort by the developers to bring people to an out-of-the-way corner of Brooklyn.

“Subsidizing an arts presence in the neighborhood is a savvy longterm investment,” Adam Forest Huttler, executive director of Fractured Atlas, an artist support organization, said. “Presumably Two Trees owns enough nearby property that they’re in a position to benefit from the economic development that inevitably follows the arts.”

Although the building has been a site of much local history, it had been largely regarded as a place well-positioned to get a makeover.

“We are realizing now that it is crazy to throw something out that has lots of life left to it,” said Mr. Alpern. “It’s like you have this fur coat that’s gone out of style, and rather than throw it away, you take it in and they fix it up to conform what people are wearing. Doing this kind of thing shows that we have finally grown up.”