Who

With business partner Michael Fuchs, Rosen presides over RFR Holding, which owns landmarks like the Lever House and the Seagram Building as well as a collection of flashy condo buildings. His wife is socialite Samantha Boardman Rosen.

Backstory

Aby was raised in Frankfurt, the son of Holocaust survivors—his father, Isak, was a real estate developer—and he first encountered his future business partner Michael Fuchs in kindergarten. (Their fathers both originally hailed from Lodz, Poland and worked together in the real estate business.) Following law school at Frankfurt University, Rosen relocated to New York in 1987 and spent three years at the British real estate firm Jones Lang Wootton. Deciding it was time to go solo, he teamed up with Fuchs in 1991 to launch RFR Holding. The timing was fortuitous: Just as Manhattan's real estate market was plummeting, they went on a buying binge, thanks to capital from their families back in Germany. The duo then turned to residential development, constructing upscale rental buildings on the Upper East Side in partnership with developer Trevor Davis, like the Michael Graves-designed Impala and Costas Kondylis-designed Eastbridge Landing. But it was their acquisition of two of the city's true trophy buildings that really put Rosen and Fuchs on the map: In 1998, they acquired Lever House; two years later they purchased the famed Mies van der Rohe-designed Seagram Building. They've since shifted their focus toward glitzy residential developments and RFR now boasts a property portfolio of some 11 million square feet of office and residential space, mostly concentrated in New York and their native Frankfurt.

Of note

Rosen has generated a good deal of press over the past few years thanks to the painfully fashionable properties that RFR has developed in collaboration with Ian Schrager, his oversized collection of contemporary art, and his high-profile presence on the social scene. In 2006, RFR and Schrager unveiled the Gramercy Park Hotel—the pricey condos, hip hotel rooms, "rock 'n roll baroque" design by Julian Schnabel, and hot spots Rose Bar and Wakiya made it one of the most talked-about new properties in town. Rosen, Fuchs and Schrager also collaborated on 50 Gramercy Park North, a 23-unit condo nearby; more recently, the trio completed work on 40 Bond, which sports a glassy green exterior fashioned by the elite Swiss architecture firm Herzog & de Meuron.

Many more projects are in the works: There's One Jackson Square, a 35-unit West Village condo designed by William Pedersen; a W hotel-condo in South Beach; and a 61-story hotel-condo named Shangri-La at 610 Lexington, designed by Sir Norman Foster. But while it's RFR's glam projects in Manhattan that get all the attention, Rosen and Fuchs have added some decidedly less sexy properties to the portfolio, too: In 2007, they purchased a collection of office buildings in downtown Stamford from Steve Schwarzman's Blackstone Group for $830 million.

For the record

His first name is pronounced A-bee, not AB-ee.

Off hours

The silver-haired real estate titan has emerged as one of New York's most prolific collectors of contemporary art: Rosen boasts a collection of around 800 works, including some 80 pieces by Andy Warhol. His Lever House office features works by Jean-Michel Basquiat, Tom Friedman, Louise Bourgeois, Gary Winogrand, and Sol Lewitt; on display in the lobby and courtyard are works by Damien Hirst, including a number of dead animals in formaldehyde. Rosen's Upper East Side manse is home to art by Francis Bacon, Jeff Koons (his good pal), Maurizio Cattelan, Christopher Wool, Richard Prince, Richard Serra (his Memorial Day is displayed in Rosen's living room) and Tom Wesselman (his Smoker #6 is located in the smoking room, naturally). A fixture at auctions in New York and London, occasionally accompanied by his art advisor Kim Heirston—and equally ubiquitous at art openings where he can be seen strutting around in the company of art-hoarding buddies Adam Lindemann, Peter Brant, and Alberto Mugrabi—Rosen has a collection so large that he employs a full-time art curator and has to regularly rotate pieces through his various homes so he can see them all.

On the side

Rosen's fashion consciousness extends beyond his involvement with the art world. For one thing, he's an investor in a number of modish restaurants around town: With John McDonald and Josh Pickard, he's a partner in Lever House (situated inside his Lever House, of course), Lure Fishbar, and Chinatown Brasserie. (He doesn't just own the high-end Chinese eatery: Rosen also paid $30 million in 2007 to acquire the historic Noho building that houses it.) Rosen was also one of the initial investors in the Core Club, the hangout for moguls who like to think of themselves as cultured; and he owns pieces of crony Peter Brant's newsprint business and publishing concern, which puts out titles right up Rosen's alley like Interview and Art in America.

Drama

Rosen may be popular in elite social circles, but he wasn't quite as popular with some of his East Side neighbors in 2006 when he announced plans to construct a 22-story Norman Foster-designed building at 980 Madison. Author Tom Wolfe sniped in a Times op-ed that it "would be hard to dream up anything short of a Mobil station more out of place than a Mondo Condo glass box by Aby Rosen." The developer tried to push ahead, enlisting pals like Tory Burch, Richard Meier, Ron Perelman, Patricia Wexler, and Larry Gagosian to speak out in favor of the project, but ultimately suffered the indignity of having the Landmarks Preservation Commission reject the plan in 2007.

Personal

Rosen has two children, Charlie and Gaby, from his marriage to his first wife, Elizabeth Wechsler; the couple separated in 2000 and finally divorced in 2004. After heartily enjoying the dating scene for a few years—his conquests included Gina Gershon and Lulu de Kwiatkowski—the generously-proportioned developer settled down anew in 2005 with socialite/psychiatrist Samantha Boardman Rosen. So far they've had two children together, Alexander Baker Rosen and Vivian Munn Rosen. The family lives in a limestone townhouse on East 80th Street and spend summers at their Southampton mansion. They also have a home in St. Barts.