He looks vaguely like Woody Allen - if Woody Allen were a tall, mumbling economist instead of a short, talkative filmmaker.
He loves parties and tennis, yet is so noncommittal in conversation that he's been known to avoid commenting on the weather.
He's Alan Greenspan - the central banker's central banker, a bureaucratic bon vivant, and indisputably one of the most powerful individuals in the world today.
As stock and currency markets gyrate from Asia to the Americas, US Federal Reserve Chairman Greenspan has increasingly taken on the role of symbolic head of the new global economy.
In recent public remarks, he has said that something must be done to calm roiling economic waters. Last week, his hints that the Federal Reserve will cut interest rates when it meets today in Washington sent a brief burst of optimism coursing through the world's bourses. Asian markets, as well as the Dow Jones, blipped up.
"Greenspan, more than any other central banker in the world, understands that this is a global liquidity crisis that will deepen and will assuredly hurt all the major economies," former Fed economist Catherine Mann told the Reuters news agency this week. "He is taking on a role as a global financial leader."
To a certain extent, the head of the US Federal Reserve has always been a preeminent player in global economics. The size of the US economy and the solidity of the dollar ensure as much.
Mr. Greenspan's predecessor at the Fed, the gruff, fly-fishing devotee Paul Volcker, was long a general in the world's fight against the inflation that ravaged much of the developed world in the 1970s and early 1980s.
Unique circumstances may have made Greenspan today's world economic commander in chief, however. At a time of turmoil, some key global economic players, notably Japan, appear to have decided that the best course of action is to do nothing. Europe, for its part, is focused on problems posed by the merger of national currencies into the single Euro.
New players such as Russia do not have the expertise or stature to lead. The US president is hobbled by his scandal problems, while administration economic officials cannot even get Congress to vote more cash for the International Monetary Fund.
THAT leaves Greenspan. As head of the Federal Reserve, he is appointed by the president - but tradition and the Fed's charter ensure some leeway for independent action.
Greenspan has said in the past the US economy is unlikely to remain an island of prosperity in a sea of troubles. And in speaking to the Senate Budget Committee last week, the usually opaque Fed chief made remarks that many experts interpreted as a hint of a coming cut in interest rates designed to help the whole world, not just the US. "We have to bring the existing instabilities to a level of stability reasonably shortly," Greenspan told senators. "I think we know where we have to go."
Many experts hope Europe would follow a US lead toward lower interest rates. Such cuts could slow the flight of money from Asia and troubled developing economies into relatively safe Western bank havens.
But who is this man whose pronouncements can send brokers' hearts soaring, or sinking, across the globe?
He's a native New Yorker. His first focus was music: He attended New York's Julliard School and toured the country for a year in the early 1940s, playing in the Henry Jerome swing band. If nothing else, friends believe, this experience of US travel gave him the ability to connect dispassionate economic theories with the individuals they affect.
"The most outstanding thing about him is he knows the American economy ... how many black left shoes are produced in Johnstown, Pa.," says friend Herbert Stein, an economist at the American Enterprise Institute here.
A swing into economics carried him straight into moderate Republican politics. He advised Richard Nixon in his 1968 campaign, and served briefly in the Bureau of the Budget.
Seven years later, he returned to government service, replacing Mr. Stein as chair of the Council of Economic Advisers in the final days of the Nixon presidency. He agreed only after being assured that Vice President Ford would keep him.
In that role, he helped formulate the inflation-fighting blueprint of the 1970s that reduced inflation from 11 to 6.5 percent.
Greenspan is also known for taking hot morning baths that last as long as an hour, with his in-box within reach. The practice began years ago to counter a bad back.
That has not kept him off Washington's tennis courts, where he is a renowned competitor. "I found his intensity remarkable and his approach shot serious," says a recent partner.
Married to NBC newswoman Andrea Mitchell, Greenspan is also famous for his syntax, or rather, the way it conceals virtually anything that could be said to be an opinion. This is partly the result of the natural reticence of Fed officials, who understand that markets hang on their every word. But it is also part of Greenspan's personality.
One friend remembers encountering him in an airport, after violent storms had almost shut down air traffic on the East Coast. Asked about the weather, the Fed chairman said hesitantly that it was "OK."
"He couldn't even bring himself to be conclusive about the weather!" says the friend.