"Oh, damn," groans Shashi Tharoor, the U.N.'s information chief, into his mobile phone. "That's very grim stuff." The sun had just broken through on a dreary Saturday morning when Tharoor, one of U.N. Secretary-General Kofi Annan's closest confidants, received news that Osama bin Laden had accused the U.N. of "crimes against Muslims" on an Al Jazeera broadcast. Tharoor, who is also an acclaimed novelist, was walking down 42nd Street toward the East River, past the orange-and-black city trucks filled with sand that protect the U.N.'s modernist headquarters. "I'll call the S.G."

Secretary-General Kofi Annan, at that moment, was on a Swissair flight from Geneva to New York. In just a few days, over 40 heads of state and twice as many foreign ministers would be arriving for the annual debate of the U.N.'s General Assembly -- originally scheduled to begin the week after September 11.

As Tharoor pauses at a checkpoint to show his I.D., he tells the guard of bin Laden's threat. "Security's already as high as it can get," he says, shrugging.

Bin Laden's jeremiad underscored a new reality: Kofi Annan is at the diplomatic ground zero of the current conflict. On any given day, Annan, born in Ghana and educated at Macalester College and MIT, will log over a dozen calls to a pantheon of world leaders -- Pakistan's Musharraf, Saudi Arabia's Abdullah, Iran's Khatami, Sharon, Bush, Arafat.

For a U.N. secretary-general, of course, the most difficult relationship is with the U.S. "Inside this building," says Fred Eckhard, Annan's spokesman, "nothing really happens without U.S. support." The conflict with Osama bin Laden and the Taliban has further complicated the relationship -- but it's also brought unprecedented opportunity. And Annan's challenge now is to foster the nascent internationalism of the U.S. while keeping the conflict in Afghanistan from becoming an even worse tragedy.

"The U.S. is the only superpower in the world," says Annan, in his liltingly accented English (it sounds more Caribbean than African). "It has been very successful, and sometimes success has its own hubris. The temptation to do it alone is a very strong one. But as the world becomes more interdependent, there are quite a lot of issues no one country can handle. We need to accept that in certain situations the collective interest is the national interest."

Even to his peers, Annan is a glamorous figure. "Kofi is the international rock star of diplomacy," says Richard Holbrooke, who was President Clinton's table-thumping ambassador to the U.N. "He has a nearly magical ability to move people through his personal charm and gentle strength."

"Kofi is the international rock star of diplomacy," says Richard Holbrooke. "He has a nearly magical ability to move people through his personal charm and gentle strength."

Rock star isn't an exaggeration. Traveling abroad, especially in Africa, he draws rapt crowds in the thousands. Even on a normal morning, as he walks by visitors waiting to tour the U.N., it is not unusual for them to break into applause.

Whereas previous secretary-generals have become identified with the U.N. bureaucracy, Annan has made his reputation as an honest broker among world leaders. "His role is like that of a constitutional monarch -- he has no real power but he encourages, advises, and warns," says Sir Kieran Prendergast, an avuncular British ambassador who is now Annan's top political adviser. "He nudges them along. And he gets on remarkably well with some very difficult people."

Within days of the attacks on the World Trade Center and the Pentagon, Congress released $582 million in U.N. arrears, ending a long policy of neglect (and, at least on one side of the congressional aisle, outright hostility) that came close to losing the U.S. its vote in the General Assembly. "The superpower realized it can't order governments to do things on their own territory," says Sir Jeremy Greenstock, Britain's U.N. ambassador. Within 24 hours, both the General Assembly, which represents all 189 member states, and the Security Council, the more rarefied executive body, unanimously passed resolutions condemning the attacks. "I'm happy to say," says Annan, "that this house reacted very effectively and very quickly."

Then, on September 28, the Security Council passed a resolution that binds member states to adapt their anti-terror laws and pursue terrorists. "That was historic," Annan says. "Normally the Security Council passes resolutions dealing with individual crisis spots. But this is something that applies to all member states around the world."

The dramatic gesture was backed by real teeth, which the U.N. rarely shows: Economic or even military sanctions will be imposed on states that provide financing, support, or safe harbor for terrorists. Rather than simply raise their hands to vote on the resolution, all fifteen council members stood in unison.

Washington, which prefers unilateral action to the U.N.'s often-tortuous multilateralism, knew it had no choice this time but to collaborate. "A lot of countries don't want to be directly in coalition with the U.S. or to be dictated to by the U.S.," says former senator Timothy E. Wirth, who is president of Ted Turner's U.N. Foundation. "But they will go along with a U.N.-coordinated coalition."

"There's a new spirit of cooperation," Annan says, building steeples with his fingers. "I'm in touch very often with Secretary of State Powell and the president himself." Powell and Annan speak several times a week.

"Powell's willingness to consult and listen is vital -- Kofi helps him understand what the world is thinking," says one diplomat close to both men. "He's candid but subtle: He can say, 'You guys are screwing up by bombing so much that you'll lose the entire Islamic world,' without actually saying it directly."

The courtship between Washington and the U.N. is still in a fragile place. "Kofi has a very close relationship with Powell, but he doesn't feel very close to other members of the administration, particularly Rice," says an eminent figure in the foreign-policy establishment. "She seems to want to keep her distance from the U.N. -- it's almost as if she doesn't want anyone to think she's soft-minded."

At 5 A.M., Kofi Annan was asleep in his townhouse at 3 Sutton Place, which he shares with his wife, Nane, a Swedish lawyer turned painter, when the phone woke him. "In the sort of business we are in," Annan said with a smile, "usually when you get a call that early in the morning, it is something disastrous."

In fact, the call was to tell him that he and the U.N. had won the Nobel Peace Prize. Whether the news is good or bad, though, Annan's reaction is marked by an uncanny equanimity. Tharoor dubs him a yogi. "He has a tremendous inner strength," says Nane, a niece of Raoul Wallenberg, the Swedish diplomat who died rescuing thousands of Jews in World War II.

Annan is a small man, hardly five foot seven, but a room's center of gravity moves with him. His style of conveying reactions with the utmost subtlety hushes colleagues, who fear they might miss a signal. "When he's displeased or angry, there's just the flicker of the eyes, or he just looks down briefly," says Sir Jeremy.

Although he is not considered an intellectual heavyweight, his admirers refer to Annan's preternatural instinct for saying and doing precisely the right thing. This, along with the moral authority he draws from not having any national interest or personal agenda -- he's spent his entire professional life at the U.N. -- explains much of his success. "He's the least ego-driven person I've met," says John Ruggie, who was Annan's chief strategist until April and is now at Harvard. "It's almost as if he removes himself from the mess and says, 'This is not about me.' It comes from a deep sense of personal security from knowing who he is."

In large part, Nane says, Annan learned who he was from his father, a hereditary Ghanain noble and elected governor whom his son has described as reserved but forceful. But Annan also benefited from an intense curiosity about the world that first took him to Macalester in Minnesota to study economics at 20, and then to postings in Geneva, Addis Ababa, and Cairo. His only time away from the U.N. was in the early seventies, when he earned a management degree from MIT. And since 1983, he and Nane, who have three children from their first marriages, have lived in Manhattan.

The Nobel committee cited Annan for promoting human rights, combating aids, and reviving an organization long paralyzed by power disagreements and meager resources. "Kofi restored the U.N.," Holbrooke says unequivocally. In awarding him a second five-year term in June, the General Assembly broke protocol for the first time in its history; the post should have gone to an Asian.

Since September 11, Annan has kicked the U.N. into higher gear, bringing a CEO's sensibility to managing the crisis. "There are times when I have to be a secretary," says Annan. "And there are times when I have to be a general and show leadership." These are such times.

At ten every morning, Annan's "Afghanistan team" gathers in the drab thirty-eighth-floor conference room beside his office. "Kofi always begins by asking about the humanitarian issues -- how much food is getting in, how many refugees are moving across the border," says John Renninger, who heads the newly created crisis group. "Then we get an update from Brahimi about his negotiations."