Eric Schmidt, CEO / Google

Although close to 20 years separate the three, their executive identities are inseparable as the triumvirate that runs Google and, according to company bylaws, they must agree on important decisions.

“If there&'s anything that&'s really important and really big, we agree that we have to agree,” Schmidt said in an interview last year. “And I prefer that, to be honest. It&'s very, very lonely if you&'re the only person with a very hard decision to make.”

Whatever it says on paper, to the outside world, Schmidt, who turns 50 this year, is the voice of reason who keeps Google&'s considerable creative energy flowing toward the right projects. Whereas Page and Brin have decorated their Mountain View, Calif., offices with beanbag chairs, it&'s easier to picture Schmidt in something more ergonomic. And while the co-founders are said to be obsessed with roller hockey, Schmidt&'s pastime—he&'s an avid pilot—seems more “adult.” Yet, like an indulgent older brother, Schmidt can overlook the sometimes quirky whims of the co-founders.

“Whereas many [Silicon] Valley CEOs would have stepped in and tried to make the company theirs, Eric&'s brilliance was in not getting in the way of the founders&' ideas,” says one longtime acquaintance. “He is not the technical vision, he is the moderating influence.”

But Schmidt isn&'t exactly a slouch in the technical department. He holds a B.S. in electrical engineering from Princeton University and earned a doctorate in computer science from the University of California at Berkeley. He was a researcher at Xerox Palo Alto Research Center (PARC) and Bell Laboratories. Schmidt perhaps made his most indelible mark at Sun Microsystems, where he led the push in Java and Internet software. And prior to joining Google&'s board, he was CEO at Novell.

Vint Cerf, who joined Google in September after sending Schmidt an e-mail asking if he could “help,” says he is impressed by how Schmidt has kept innovation a top priority in Google&'s post-IPO existence. Schmidt encourages engineers to spend 20 percent of their time on independent projects, working in three-person teams. “The culture that allows any employee time to innovate is both gutsy and smart,” Cerf says. “Some of the best ideas come from that open invitation.”

While encouraging the company&'s youthful energy, “he&'s also responsible for making sure the beehive is actually producing honey,” his acquaintance says. And Schmidt is definitely doing that. Google reported a dramatic 96 percent leap in revenue to $1.6 billion for the quarter ended Sept. 30, while income rose more than sevenfold to $381 million. The company&'s stock is heading into the stratosphere.

Schmidt has always been uncomfortable being singled out for recognition. Maybe it&'s just as well. He has plenty of things to worry him: There&'s the fight with the publishing industry over the company&'s plan to digitize books, and Google&'s instant-messaging and voice communications aspirations are pitting it against America Online and Yahoo.

And then there is the escalating competition with Microsoft. Although Google has a long, long, long way to go in the corporate marketplace, its cult-like following could create traction behind products such as Google Desktop Search for Enterprise, which in essence co-opts the Windows user interface. And Google&'s first formal channel effort, the Enterprise Professional Program, which seeks to entrench its search technology in businesses to better mine corporate data, specifically targets Microsoft partners.

“[Schmidt] fits the current job perfectly. He&'s unorthodox in the right ways at the right times,” says John Seely Brown, former director of Xerox PARC, where he knew Schmidt.

Chances are, those times will become more frequent in the year to come.