Developer Aby Rosen considers himself a preservationist.The active art collector and top donor to the Municipal Art Society bought and restored two landmarked office buildings on Park Avenue, the Seagram Building and the Lever House, for which he won a preservation award.

But his latest project is causing an outcry from Upper East Siders who say the design for a 22-story elliptical, glass apartment building on top of the limestone Parke-Bernet Gallery building on Madison Avenue mocks the neighborhood’s character and the definition of a historic district.

Mr. Rosen, the president of RFR Holding LLC, said the proposed tower, across the street from the Carlyle Hotel between 76th and 77th streets, would be a welcome breath of fresh air in the neighborhood.

“The Upper East Side needs new progressive architecture,” Mr. Rosen said. “Historically, the people who lived there were a driving creative force behind New York City. Unfortunately, now the Upper East Side has lost a little bit of its progressive luster to downtown.”

The project’s award-winning architect, he noted, Lord Norman Foster, was recently praised by critics for his design of the new Hearst Tower on Eighth Avenue, a 47-story addition to an existing, landmarked base.

Last night, a member of Lord Foster’s firm presented designs in front of a crowded community board meeting. Several neighbors spoke out against the tower. One local resident, Daniel Goldberg, said the proposal was “like a glass dagger plunged into the heart of the Upper East Side.”

The co-chairman of the Defenders of the Historic Upper East Side, Teri Slater, said the project belongs elsewhere.

“We nearly fainted when we saw the renderings,”Ms. Slater said.”The reason people want a historic district is they want to be preserve a context. If you propose something totally out of context, it defeats the purpose of having a historic district.”

“Our area is vital enough. We love it the way it is, and we will fight to protect it,” Ms. Slater said.

Designated in 1981, the Upper East Side Historic District stretches from 59th Street to 78th Street, roughly between Fifth and Lexington Avenues. It contains hundreds of mansions, townhouses, and apartment buildings erected by the city’s wealthiest citizens at the beginning of the 20th Century. As part of that district, Mr. Rosen’s project must be approved by the Landmarks Preservation Commission, which has scheduled a public hearing for October 24th. Another Community Board meeting is scheduled for tomorrow.

The president of the Municipal Art Society, Kent Barwick, was the commissioner of Landmarks when the historic district was designated.

“We weren’t trying to freeze an area in time. We wanted there to be opportunities for good, new architecture but still protect the qualities that make it special,” Mr. Barwick said.

He would not comment on Mr. Rosen’s application until he previews it with other city civic organizations on Thursday.

The executive director of the Historic District Council, Simeon Bankoff, said the building’s style, materials, and scale is “astonishingly at odds” with the area’s character. He said that the Landmarks commission should not be swayed by Lord Foster’s fame.

“It is not about the quality of the architecture. This is more about what it means to have a historic district,” Mr. Bankoff said.

The director of the historic preservation program at Columbia University, Paul Byard, said Lord Foster’s design was “moderately interesting,” “wellcomposed,” and “certainly could be promising,” but he predicted conflict. He said the Upper East Side is a notoriously difficult place for more contemporary designs.

“There will be blood on the floor,” Mr. Byard said.

Upper East Side preservationists most recently fought the Whitney Museum of American Art for about two and a half years over a proposed addition just a block and a half from Mr. Rosen’s proposed tower.A modified design received final approval earlier this year by the city’s Board of Standards and Appeals, and a lawsuit soon followed.

Mr. Byard said that the Landmarks Commission is increasingly faced with pressure from some preservationist groups to only approve designs identical to a neighborhood’s existing character. That leaves the commission with only legal oversight, rather than architectural oversight, he said.

“By insisting on a rule of sameness, you are taking away the jurisdiction of the Landmarks Commission, which is to deem appropriateness,” Mr. Byard said.

Mr. Rosen, the developer, said he bought the Parke-Bernet Gallery more than two years ago, for roughly $120 million, with the intention of adding a rooftop tower on top. The gallery was built in 1950 and renovated in about 1960, when the building’s public garden was replaced with a fifth story of offices.

Mr. Rosen said the total cost of adding the tower would be about $180 million.The public garden would be restored and the tower would be built 120,000 square feet smaller than what would be allowed under the existing zoning, he said. The tower would contain about 18 full-floor units and duplexes spread spaciously on 22 floors.

“They are going to be very pricey, but they will be beautiful and rare,”Mr. Rosen said. “We are creating a new landmark between the Whitney and the Guggenheim.”

Because the proposed development would exceed the allowable bulk allowed under zoning regulations, a special permit must be approved by the city’s Planning Commission and the City Council.

The local City Council member, Daniel Garodnick, said he is concerned about the proposal and will monitor plans.