Brin gave a parallel answer: “A lot of it is common sense, a combination of common sense and questioning rituals. Experience is a benefit, but it can also be a handicap.” He also attributes their success to their math backgrounds and a thirst “to be precise.” The idea to give employees 20 percent of their time to pursue their own passions he credits to graduate school, where “you’re always going off” on your own projects. Stanford was a huge influence: its bikes and buses, its open cafeteria tables and time to work on your own projects. “They wanted to replicate the Stanford culture in the business world,” said Ram Shriram.

The precision argument is picked up by senior vice president of Operations Urs Hölzle, who said the logic flows from a focus on the user. Start there, and it is relatively easy to decipher whether users want a Google home page cluttered with ads, or want relevant ads, or want to rapidly move to different sites. “They predicted things that did not make sense to me, but turned out to be true. Larry said, ‘The ad results have to be better than the search results.’ I thought he was wrong. Yet today studies show that people value the ads as an essential part of their search results.”

One of their mentors at Stanford, Terry Winograd, thinks their “clear, coherent point of view” is “an engineering point of view: Don’t assume things are done the right way because they were always done that way. Question everything.” And after you question, revert to “an engineering optimization attitude: ‘Make it more efficient.’” What stands out to another Stanford mentor, Rajeev Motwani, the Stanford professor Brin remained closest to and who died in a tragic accident in 2009, are their one-word questions: “The number of times they made me change my opinion by asking, ‘Why?’ They asked like a child.”

It would be a mistake to ascribe Google’s success to the generic category of engineers. Larry Page brilliantly conceived search, and Sergey Brin’s math skills were vital to its success. But Google also succeeded because it forged teams of engineers who were not territorial, who formed a network, communicating and sharing ideas, constantly trying them out in beta tests among users, relying on “the wisdom of crowds” to improve them. Building communities of engineers and hackers and users was the ethos they shared. They believed it was virtuous to share, for it embraced the construct framed by Eric Steven Raymond in a paper originally presented at a conference of Linux developers in 1997, “The Cathedral and the Bazaar.” Instead of a solitary engineering wizard crafting software as if it were a cathedral and releasing it when perfected, Raymond argued that the Linux model was more like “a great babbling bazaar” that would ignite the creativity of communities of engineers and users. This ethos was one that infected Page and Brin and Google engineers, led them to the clarity of a free search engine designed to serve users.

Eric Schmidt had another theory: Page and Brin actually have more experience than their age suggests. He recounted a recent discussion he had had with Page. He and the founders were upset with a product user interface presentation they attended. Page said the problem was that the engineers were young and had no experience. “The reason you and I agree on this is that I started on this when I was very young, and I’ve been thinking about it for a long time,” Page said. At first, Schmidt was stunned, wondering how Page grouped himself with someone who was two decades older. Then it dawned on him that Page nearly matched him for experience. Like Brin, he said, “He looks like a kid to you, but he’s been in the industry as long as I have in a way.”

The experience of the founders stems, as well, from four things they shared. First, each was raised in an academic home, where clear thinking was prized. They were trained to be precise. Each also “are quintessential Montessori kids,” said Marissa Mayer. “They didn’t have a lot of structure. They got to do what they want to do. They were taught to question authority and think for themselves. They fundamentally believe that people on many levels know what’s best for themselves. Like the Montessori kid who paints when he wants to paint.” Montessori, Page said, taught Brin and him “to question everything.” A third vital shared life experience was Stanford. The fourth was that Page and Brin shared each other. “There’s kind of a strength in the duo,” said Coach Campbell. “So when they come out the door at the other end, they are even more convinced than they were going in.”

“We agree eighty to ninety percent of the time,” Brin said of his relationship with Page. Page thinks they agree about two-thirds of the time, but said their disagreements are usually over small things. “If we both feel the same way,” Page said, “we’re probably right. If we don’t agree, it’s probably a toss-up. If we both agree and nobody else agrees with us, we assume we’re right!” He smiled as he said this, an awkward, tight smile, yet one that conveyed both merriment and resolve. “It sounds like a tough thing to say, but that’s sort of what you need to do to make progress.”

Susan Wojcicki, who rented them her garage, believes they gave each other strength-strength “to be different. They think alike. They had a shared vision. So when things got tough, they were able to support each other in being different.” They don’t always agree, said Jen Fitzpatrick, who is Google’s engineering director and was among the first thirty Google employees, but “having a mental sparring partner is a good way to drive your own thinking.”

“Having the two of them being completely in sync” is a huge advantage, said Kordestani. He remembers his experiences as an executive at Netscape, where the three senior executives-founder Jim Clark, CEO James Barksdale, and the browser’s inventor, Marc Andreessen-“were not in sync.” Pulling in different directions, Netscape lost its focus.

Page and Brin bucked each other up in another way: they burned with an idealism that sometimes bordered on messianic. They launched Google with a fervent belief that advertising tricked people to spend money, that the Internet would foster a democratic ethos that would liberate people. They gave employees their 20 percent time, Page told Schmidt, in order “to force a conversation” with managers, removing some managerial power.

There is a real sense of loyalty to Page and Brin at Google. Their vision has made Googlers obscenely rich. Employees love the freedom that the 20 percent time and generous benefits grant. Like Steve Jobs or Bill Gates, their knowledge can be intimidating, though terror is not commonly part of their motivational arsenal. Their approach can be subtle. Sheryl Sandberg recalled a project she supervised in her role as vice president, global online sales and operations. The story she related could be interpreted as an illustration of a company careless about how much is spent, or as a reason employees like Sandberg saluted the founders. At the time, her project awarded free search ads to nonprofit groups. “Some companies would be worried about the bottom line. Larry and Sergey just wanted to know why the program was not bigger, faster,” she said. She increased the size of the effort-too fast, it turned out. “We were giving much more ad inventory to a handful of nonprofits than we should have.” She trekked to the founders’ office in Building 43 to explain. Page was there alone, and she explained her “really big mistake,” said she “should have noticed,” and apologized.

Page interrupted her, she recalled. “He said, ‘I’m so glad these are the kinds of mistakes you’re making because it means you’re moving quickly and doing too much. I’m going to be very upset when the mistakes you’re making are by going too slowly and missing opportunities.”’ She volunteered a ten-point plan to avoid similar mistakes, asking if he wanted to review it.