(FORTUNE Magazine) – DAVID BLITZER It's up to Blitzer, 54, chairman of the Standard & Poor's Index Committee, to decide which companies go on and off S&P's benchmark 500-stock index. The committee adds or drops about 25 a year. For the lucky ones, the ramifications are massive--such as a 5% to 8% stock price bump within the first week, mostly due to buying by huge index funds.

WILLIAM CHANDLER III Chandler, 52, is the law of the land in business--and that land is Delaware. That's where more than half of the FORTUNE 500 are incorporated. As a judge at the state Court of Chancery, he has issued key rulings that permitted the merger of Hewlett-Packard and Compaq and a shareholder lawsuit against Disney for Mike Ovitz's huge severance package.

JOHN CRAIN The backbone of the Internet is run by 13 "root servers" around the world. At the Internet Corporation for Assigned Names and Numbers (ICANN), John Crain, 37, heads the tech team that keeps them up and running. "The entire Internet eventually comes through" these machines, he says. Where in Los Angeles is his root server located? Luckily Crain's not telling.

GAMAL HELAL Remember that photo of Clinton and Arafat at Camp David? Or the one of Cheney and Amir Hamad bin Khalifa Al-Thani in the Wajbah Palace in Qatar? That's Helal, 49, in the middle of both. The chief White House translator for 22 countries across the Middle East and Africa, he bears the burden of making sure George W.'s "strategery" comes across clearly in Arabic.

PETER NICULESCU You probably owe him your house. Niculescu, 43, who's from New Zealand and used to work at Goldman Sachs, manages Fannie Mae's $812 billion mortgage portfolio business. It brings in two-thirds of the revenues for a company that guarantees 25% of the mortgage debt outstanding in the U.S. Oh. Well. Thanks, Peter.

MIKE PEREIRA The NFL's 53-year-old officiating director does his best to teach 119 part-time employees to make split-second decisions that affect hundreds of players and coaches (and millions of fans) every football Sunday. Which doesn't make it easier when a zebra has to stick his head into that black box to replay and review a call--in the spotlight, alone.