On Feb. 13, after a conversation with his friend Vernon Jordan and his wife, Senator Hillary Rodham Clinton, a chastened Mr. Clinton emerged from behind a dark glass door at 55 West 125th Street in Harlem to announce a change of heart. "I have decided to locate my office in this building," he told the mob of reporters and cameramen, and an ecstatic throng of passers-by. "If," he cautioned, "we can work it out."

"For the former President to be working on 125th Street," said Democratic State Senator David Paterson, "I would equate it with man walking on the moon."

If that's the equation, then Charles Rangel is the equivalent of Michael Collins, the pilot of Apollo 11. For it was Mr. Rangel, the longtime Harlem Congressman who helped launch Hillary Rodham Clinton's Senate candidacy, who brought Mr. Clinton on his unprecedented journey uptown. Except for the Harlem empowerment zone, Mr. Clinton is effectively the biggest piece of pork Mr. Rangel ever brought back to his Congressional district. Having a high-profile former President in Harlem not only changes the way in which the power elite views its little island, but could also transform the business corridor along Harlem's most famous street.

Mr. Rangel said that when Mr. Clinton called him at home on Feb. 9 to inquire about space in Harlem, he thought immediately of the building at 125th Street. Mr. Rangel himself had offices in the building when it opened 20 years ago, and in urging Mr. Clinton to locate there shortly after last fall's election, he'd reminded the President of the large rally his wife had held on the block just before Election Day.

"Harlem was always there for the President, and it was the birthplace of the Hillary Clinton political campaign," the Congressman said. "Whenever [business] people are thinking about coming to Harlem, they want to know who's there. Now we got a President."

For Mr. Clinton, Harlem offers nothing but positives. Instead of a suite of offices in Carnegie Tower costing taxpayers at least $750,000 a year, Mr. Clinton will make do with office space costing about $200,000. He will be welcome in a neighborhood that clearly loves him-the crowd on 125th Street cheered his every move and word. Those midtown Manhattan social arbiters who have been talking trash about the Marc Rich pardon-well, they needn't worry about bumping into the former President at the Four Seasons and wondering what to say and how to say it. Mr. Clinton will chow down at Sylvia's, thank you very much.

And Mr. Clinton can enjoy a few private chuckles over the misery he's causing the midtown masters of the media, who believe in the power and the glory of their little neighborhood. When Mr. Clinton seemed destined for Carnegie Tower, the midtown power elite was pleased in an ever-so-condescending way. Where else, after all, would a youthful, vital former President base his operations but in midtown Manhattan? Now, Mr. Clinton has decided to build his center of power 75 blocks from the so-called center of the universe. Yes, Mr. Clinton will enjoy their discomfort.

It was clear during the Harlem press conference that the President needn't worry about his new neighbors. The Rich pardon, the headlines about dubiously acquired flatware-they simply didn't exist. After he finished speaking, Mr. Clinton plowed through the crowd, shaking hands and high-fiving as he went.

"You go, Bill! You go!" shouted one onlooker.

"We love you, Bill! You're still our President!" said another. A pregnant woman asked Mr. Clinton to rub her belly for good luck. Mr. Clinton ducked inside a restaurant, Bayou, for lunch; the crowd built steadily for the hour and a half he was inside.

Meanwhile, back at the reception desk at 55 West 125th Street, dreadlocked security guard Leonard Terry was rubbing his eyes. "Trying to bring down the stress," he said. He'd heard about the big secret two days before, and Mr. Clinton's visit had given him his first taste of how life at the building was about to change. "It'll be a little more hectic," he said, "so I hope they give me a little bit more pay."

When Mr. Rangel was trying to come up with a Harlem office building for Mr. Clinton, there wasn't exactly a long list from which to choose. In fact, 55 West 125th Street is the only building classified as Class A in the entire neighborhood. Its story encapsulates, in a way, the recent history of Harlem. It was built in the 1970's by Charles A. Vincent, a political figure who served in the Nixon administration. Mr. Vincent eventually ran into financial problems, and the building was sold to absentee owners, who let it deteriorate. In 1998, Steven C. Williams, a local real estate investor and a board member of the now-disbanded Harlem Development Corporation, bought the building in a partnership with the Cogswell Realty Group. The new owners have spruced it up in an attempt to harness the momentum of recent development along and near 125th Street.

Today, the building houses a number of government agencies, charitable foundations, and Local 420 of the American Federation of State, County and Municipal Employees-a far cry from the tenants in Carnegie Hall Tower, who included Steve Case, Barry Diller and assorted other luminaries, but a natural constituency all the same.

A Brief Tour

Mr. Clinton's tour of the building took him past Mr. Terry, the security guard, through the building's beige marbled lobby and past an Alvin Hollingsworth mural picturing women dancers in African headdresses. He saw the 12th floor, painted blue with frescos of fish around the walls, and the 14th, with its views of Central Park and midtown beyond. If he looked closely out the window, Mr. Clinton might have been able to see Carnegie Hall Tower, which captivated him with its own views of the park-looking south to north, instead of north to south.

If Mr. Clinton noticed the considerable luxury differential between this building and Carnegie Hall Tower-the building is suffused with a faint deli smell, and the elevators, though new, are erratic-he didn't let on.

"He just kept saying, 'This is wonderful,'" said Cogswell's Michael Skurnick, who showed him around.

For a few hours, there seemed like there might be a problem in the works-the 14th floor, which is only around 8,000 square feet and thus perfect for Mr. Clinton's purposes, was leased in December to the city's Administration for Children's Services. Mayor Rudolph Giuliani's press office, sounding agitated, let it be known that the Mayor would address the issue at his daily press conference. But when the moment arrived, Mr. Giuliani was downright conciliatory.

"We are certainly willing to listen to an offer. Maybe they can make us an offer we can't refuse," he said, embarking, as is his custom, on a Godfather riff. "I think it would be a very good thing for the former President to have office space in New York. I think it would be particularly good for him to have it in Harlem. We would like to accommodate that interest, but we can't be unmindful of the concerns of the children, either."

On the way off the 12th floor, Mr. Clinton introduced himself to receptionist Deborah Davis. "He said he would be up on the 14th floor and visiting us often," Ms. Davis said.

That wasn't, of course, the plan as of a week ago. Mr. Clinton settled on Carnegie Hall Tower in January, and officials from the federal General Services Administration were in the late stages of lease negotiations with the building's owner, the Rockrose Development Corporation, when Mr. Clinton decided to move uptown.

And the power map of Manhattan shifted accordingly.

-Additional reporting by Elisabeth Franck, Rebecca Traister, Greg Sargent and Andrea Bernstein.

This wasn't the U.N. It was the green marbled lobby of Carnegie Hall Tower, at 152 West 57th Street, where the guards stand sentry in front of a security desk. Why so vigilant? A computerized directory on the wall says film and television executive Barry Diller has offices there. So does former Viacom and HBO chief executive Frank Biondi. Music-industry power broker Allen Grubman is on the 30th floor. Jerry Seinfeld is in negotiations to lease the 55th floor.

The diligent security detail is part of the package. Carnegie Hall Tower is the kind of office building where a certain type of millionaire–the kind who winters on Parrot Cay, skis in Aspen, lives in the Dakota–runs a private business in plain sight. It's heavy on people in the entertainment business, Manhattan arrivistes and those attempting to reinvent themselves in the Second Act of their lives. They require the public's attention, while claiming that they just want to be left alone.

Bill Clinton will fit right in.

At least, that's been the verdict ever since it leaked a couple of weeks ago that the ex-President was close to a deal to lease the 56th floor of the 60-story tower, at the tippy-top-of-the-market rent of around $90 a square foot. "That building fits him like a glove," said one real estate broker. "It's a building for currently successful scoundrels …. You have to have the money, but it's not really high-class."

Others who know the building say it's a lot of fun: the type of place where you'll see Mr. Diller milling around the lobby, and where you used to run into Tina Brown barefoot in the elevator, or mistakenly find Eddie Murphy's magazines in your mail.

For all its star power, Carnegie Hall Tower has lived a fairly anonymous existence until recently. Then Mr. Clinton came along looking for office space, making news from Chattanooga to Des Moines, and Carnegie Hall Tower is famous. And it has started to act that way. Steve Morrows, the executive who manages the building for Rockrose Development Corporation, agreed to give a tour of the building for this story. But on Jan. 26, Mr. Morrows curtly explained that the tour was off. "We have a P.R. agent now," he explained.

The owners of Carnegie Hall Tower had pulled a Denise Rich: They've hired Howard Rubenstein to deal with the building's sudden stardom. "It's just not the right time" for a story about the building, explained Steve Solomon of Rubenstein Associates. Mr. Clinton had yet to sign his lease, and there was no guarantee he would. The building, he said, would rather be left alone.

So why the P.R. guy? Because Carnegie Hall Tower has attained a certain critical mass of celebrity, said Billy Cohen, the Newmark Company broker hired to fill it when it opened in 1991. "Just riding through the elevators, it's a very happening space," said Mr. Cohen, who stocked it with an eccentric roster of machers , movie stars and media executives. Then, "it was totally a lemmings thing. And it's still going on today," he said. "That's what sucked Clinton in."

There's Mr. Diller at USA Networks' offices on the 42nd floor. Erstwhile entertainment executive Frank Biondi is now a venture capitalist on 46. Stanley Jaffe, producer of The Accused , is on 52. Director Robert ( Kramer vs. Kramer ) Benton is on 26. Mr. Grubman, whose law firm represents everyone from Madonna to Bruce Springsteen, is on 30 and 31. Then there's Mr. Seinfeld, who wants the space right downstairs from the President, on 55.

Representing the new economy is Mr. Case and Bob Pittman of AOL, who, a source familiar with the tenant roster said, have private offices on the 27th floor. Swinging hedge-fund manager Mark Kingdon is on 50, and there are a half-dozen venture capital firms.

There is also the obligatory assortment of filthy-rich foreigners. A billionaire Saudi family, the Juffalis, are on the 58th floor. Nathaniel Rothschild, the handsome scion recently named the second-richest noble under 30 by The Observer of London, is a hedge-fund manager at Atticus Capital, on the 45th floor.

It's an impressive assortment of names, despite the fact that Carnegie Hall Tower came on the market in the midst of one of the toughest real estate markets in memory. Carnegie Hall had allowed Rockrose to build the tower, which also contains rehearsal space, in exchange for around $75 million in rent over 25 years. It was built without an anchor tenant. Though architect Cesar Pelli's design won raves, the building was strangely skinny–just 500,000 square feet spread over 60 stories. At a time when other new buildings stood empty and developers were going belly-up, Mr. Cohen lured his real estate friends to the building by holding his son's briss on the then-empty 60th floor. (The ploy worked–developer Steve Rosenberg still occupies that space.)

Mr. Cohen targeted fashion designers for the lower floors, entertainment companies upstairs and, on top, "pivotal power brokers." The building had straight-on, unobstructed northern views, a location near the entertainment meccas and, often, just one office per floor to accommodate egos.

On a conference call, Mr. Cohen and Mitchell Arkin, a Cushman & Wakefield executive who worked for Rockrose when Carnegie Hall Tower went up, reeled off notable tenants: "Marvin Traub, who was the chairman of Bloomingdale's …" Mr. Arkin began. "His toilet looked out over the park!"

The Wathne sisters from Iceland–Thorunn, Berge and Soffia–took space for their fashion company on the 48th and 49th floors. "They weren't [triplets], but they all dressed alike," Mr. Cohen said.

"They had three little white dogs," said Mr. Arkin. "We were always afraid the elevators were going to crush the mutts."

Eddie Murphy leased space on the 47th floor. "Murphy came in in disguise," Mr. Cohen said. "He didn't want anyone to know he was in the building." He installed a shower, a bar and a screening room, then left the building a couple of years ago, but not before his cover was thoroughly blown when staffers of Talk magazine–another former tenant–began mistakenly receiving his copy of Variety .

One assistant said that last month, she received a phone bill addressed to "Natalie Merchant."

People in the building affect disinterest, though they remember these incidents in vivid detail. One executive said she'd just seen

Barry Diller in the lobby "waiting for whoever, no big deal." She also recalled the night, when Talk was still on the 55th and 56th floors, she found Tina Brown in the elevator "standing in her stocking feet with her Manolos in her hand." Another time, when Kenneth Cole had space in the tower, she ran into him "with one of those scooters–he commuted to work on one of those!"

Mr. Arkin had his own story. "I get a call from the front desk," he remembered. "They said, 'We got a guy here, he's a bum, but he says he's Bob Dylan.'" Mr. Arkin rushed down. "The guy was getting on the elevator... I saw him and I said, 'That was Dylan!'"

Not surprisingly, the building has become a hotbed for rumors–that Chris Rock, Arsenio Hall, Sidney Pollack or even Martha Stewart are tenants. (She's not.) One tenant said: "I think Spin magazine is here. And maybe a record label or recording studio, because there are rappers in here all the time."

These days, all the rumors are about Bill Clinton. "I understand that President Clinton wanted [music-industry executive Stephen Swid's] space because it was beautifully outfitted," said Daryl Roth, who is producing Wit and Proof , and has had offices on the 21st floor for six years. "But [Swid]'s not moving!"

For all the excitement–after all, the entertainment business opened its hearts and wallets wide for the Clintons–many tenants worry that their new neighbor and his security detail will ruin things at Carnegie Hall Tower. "I wouldn't say I'm looking forward to it," Ms. Roth said. "I would say that I think it's fascinating."

Mr. Seinfeld fell in love with the building's views before the President did, but that won't alter his plans, said the comedian's publicist, Elizabeth Clark, since "he's a huge Clinton fan."

Mr. Swid, sitting at a desk in his 57th-floor offices with his back to a panoramic window overlooking Central Park, said, "I can understand why the President chose [this building]." A former co-owner of Spin (hence the rumor) who now buys music libraries, he conceded that there is some uneasiness about having Mr. Clinton in the building. "I think some people are excited and some are not," he said. "There are people who are more personally oriented than community-oriented."

Mr. Swid counts himself in the latter group. He gave money to Mr. Clinton's re-election, attended one of those famous White House coffees and proudly hangs a picture of himself and Bill Clinton on his wall. He said Mr. Clinton did come in and look around his offices before settling on Talk 's old space. Mr. Swid said the landlord offered him some money to move out before his lease was up.

He had considered leaving before, but won't now. "I benefited under his leadership," Mr. Swid said. "Where this President is, I like to be."

Still, he'll play it cool. "It would be presumptuous of me to go down and see the President," he said. "If the President wanted to come up and say hi to me, I would be honored."

With his Jan. 20 eviction date looming, President Bill Clinton is close to a deal to lease a suite of offices occupying a full floor near the top of the Carnegie Hall Tower, at 156 West 57th Street, a real estate executive familiar with the deal told The Observer.

And as the President goes West (Side), Senator Hillary Rodham Clinton is setting her eyes on the East. On Jan. 11, she signed a deal to lease 7,500 square feet of space in an office building at 780 Third Avenue, real estate sources told The Observer.

At the Carnegie Hall Tower, Mr. Clinton will be taking digs befitting a post-POTUS. While his office will almost certainly be square, not oval, from the top of the 60-story tower "the views are to die for," said one person who has offices there. Central Park South and the verdant expanse of Central Park lie directly to the north, and Times Square, Rockefeller Center and the rest of the city's skyline soar to the south. And if Mr. Clinton finds himself going stir-crazy, he can always head downstairs and hang out with his pal Barry Diller; the entertainment mogul has offices on the 40th floor.

A White House spokesman had no comment yesterday. Steve Morrows, executive vice president of Rockrose Development Corp., said, "right now I have no comment." Sources said that, at $85 to $90 a square foot, it would be a pricey deal, even by Manhattan real estate standards. As with other ex-president's, Mr. Clinton's office expenses will be paid for by the taxpayers.

"The Clintons have determined that they are going to live first-class, and clearly that's what we're talking about here," the real estate executive said.

Indeed, at 780 Third Avenue, Mrs. Clinton will be living considerably better than her predecessor, former Senator Daniel Patrick Moynihan, who had offices in the Chrysler Building. Mrs. Clinton wanted something newer, with a better technological infrastructure, and the 50-floor red-granite tower, built in 1984 and located between 48th and 49th streets, would seem to fit the bill. Mrs. Clinton's offices will be midway up the building's tower, sources said.

When she's in the office, Mrs. Clinton will be within easy walking distance of Senator Charles Schumer's offices right across the street--to say nothing of the Waldorf Astoria, one of the President's favorite Manhattan spots, and Grand Central Terminal, making for an easy Metro North commute to Chappaqua.

Jodi Pulice of JRT Realty Group, the building's managing agent, declined to comment yesterday. But according to the building's Web site, space on a lower floor is being marketed at $63 a square foot. Since this will be Mrs. Clinton's local Senate office, taxpayers will be picking up the tab.

Mr. Clinton had been looking at 780 Third Avenue himself, one source said, but decided to go elsewhere when his wife decided to move in.

The President did some office-hunting on Jan. 7, after attending his wife's ceremonial swearing-in at Madison Square Garden. He seemed particularly taken with 30 Rockefeller Center; but according to a person who has spoken with Jerry Speyer, whose Tishman-Speyer Realty owns the landmark site, security concerns nixed that idea. The public plaza below his office window would offer a potential staging ground for protesters and well-meaning gawkers, and getting Mr. Clinton in and out of the building would present numerous logistical problems.

By contrast, protesters--or those with more dubious intentions--wouldn't last long against the constant crush of pedestrians along 57th Street. And a person with offices in Carnegie Hall Tower could easily imagine Mr. Clinton slipping out the back door, on 56th Street, with a minimum amount of hassle. There's a parking garage located right next door.

Best of all, the tower's floors are relatively small near the top, allowing the President to take an entire floor. That would allow the Secret Service to control elevator access to the offices, and assure that the only friskings going on will be those Mr. Clinton may choose to perform himself.