They rented a cinder-block house in a multiracial, working-class suburb of Baltimore, near the University of Maryland. As in Moscow, they were poor, relying on the support of local Russian Jews. “My parents sort of lived in the dining room,” Sergey remembers. “There was no wall between the dining room and the kitchen. They used that as their bedroom.” Eventually, Michael became a professor of mathematics at the University of Maryland, where he specializes in Riemannian geometry; Eugenia Brin became a scientist at NASA’s Goddard Space Flight Center. They had a second son, Sam, fourteen years Sergey’s junior.

Sergey enrolled in the local Montessori school where classes were comprised of students in a three-year age range. Typical of Montessori programs, the school adapted itself to the child. “It’s not like somebody is telling you what to do,” Sergey said. “You have to plot your own path.” Because he initially spoke little English, he retreated into math puzzles, science projects, and maps. For his ninth birthday, his parents gave Sergey a Commodore 64 computer, a seminal gift for a man who now gleefully describes himself as a nerd. Some years later, when a friend got an early Macintosh computer, they began to devise artificial intelligence programs and software to simulate gravity.

Sergey’s prowess at math was encouraged by his father, a stern tutor, who sometimes graded student papers with the salutation “My sincere condolences.” Family meals featured intense discussions. Sergey was not much interested in listening to music or watching TV Nor was he an avid reader of books, though he was engrossed by the life of Richard P. Feynman, a winner of the Nobel Prize in Physics who “not only made big contributions in his field,” Sergey once said, but wanted to be “a Leonardo, an artist” as well as a scientist. “I found that pretty inspiring.” Although he says he “probably had more nerdy interests than most of my peers,” his heroes-Feynman at a young age, Steve Jobs and Warren Buffett later-suggest the breadth of his ambition.

He was also a rebellious child. When he was thirteen, his parents took him to visit the Soviet Union and he threw pebbles at Soviet policemen, causing a scene that his parents defused only by pledging to the irate authorities that he would be severely punished at home. Sergey is still very emotional about autocratic governments and anti-Semitism. But even though he was raised as a Jew and attended Hebrew school for a few years, he was nonpracticing, did not have a bar mitzvah, and was put off by traditional Jewish celebrations, which he once told an Israeli reporter he “associated with getting lots of gifts and money, and I was never comfortable with that.” When he was married on an island in the Bahamas in May of 2007 to Anne Wojcicki, cofounder of 23andMe, a genetics research company, the couple stood in bathing suits under a chuppah, the traditional Jewish wedding canopy, but no rabbi officiated.

Then, as now, he was uncomfortable with introspection. Asked by the same Israeli reporter if it was a coincidence that his wife was Jewish, he said, “I believe there are lots of nice non-Jewish girls out there. My wife is, I guess, half Jewish.”

So was it a coincidence, the reporter pressed, that his wife was half Jewish?

“That wasn’t a concern for me,” he responded. “I don’t know, maybe it was for her.”

I once asked him, “What part of your success do you trace to qualities in your parents?”

“It’s hard to say,” he answered.

After much coaxing, he added, “A certain love for science and learning and the beautiful mathematical things I have been able to put into practice is part of my upbringing.”

He attended Eleanor Roosevelt High School in Baltimore, a public school where muscles counted more than brains. This setting didn’t diminish Sergey’s cocky swagger, though, and he blitzed through in three years, gathering enough college credits there to allow him to also graduate from the University of Maryland in three years. Although he was just nineteen, Sergey flourished at college, where he was a math and computer science major and was treated by the faculty as a peer. “I was a pretty advanced student,” he said.

After graduation, he received a National Science Foundation scholarship to study computer science at Stanford, where he believed he was “better prepared” than classmates. His special interest, data mining, was a relatively new field in which computers are used to extract and analyze information from enormous fields of data. He expected to get a Ph.D. and maybe become a professor. As at Montessori, he worked at his own pace. His father once told authors David Vise and Mark Malseed for their book, The Google Story, “I asked him if he was taking any advanced courses one semester. He said, ‘Yes, advanced swimming.’” Craig Silverstein, a fellow data-mining student who would become Google’s first employee, remembers that Sergey rarely studied, yet “he passed all his tests in the first year, and didn’t take any in the second year. Already he had this reputation as a kind of genius.” Brin recalled taking eight comprehensive tests: “When I first tried, I passed all seven. The one I thought I was best at, I didn’t pass. I went to the prof and debated the answers. I wound up talking him into it. So I passed all eight. I think I was the only one.”

Brin was athletic but uninterested in team sports; he lost himself instead in gymnastics, swimming, Rollerblading, and biking. Still, Brin was more outgoing than many self-described geeks and enjoyed playing practical jokes. He also took on extra projects that aroused his interest; a typical project was the numbering system for the rooms in the Computer Science Building (donated by Bill Gates, who would become a nemesis). In the building, each room was identified with a four-digit code, which Brin felt did not convey the most useful information to the building’s tenants. “We were offended at having four-digit numbers when you don’t have ten thousand rooms,” he said. Along with computer science professor Vaughan Pratt, he set out to devise a better system, one that would enable someone leaving a given room to calculate the distance to his destination. “We came up with a sensible three-digit numbering system. It was quite elegant. Most buildings are numbered in a really stupid way. The architect or somebody sits down with the blueprint and they collate across and they number things. It looks great to them when they are looking at the blueprint. When you’re actually walking around, it makes no sense at all. The Gates building is fairly simple. I just had the numbers roll around the building. Even numbers were exterior, odd numbers were interior… The second digit told you how far around the building you had to go. It was very intuitive, if I may say so myself.”

THE SERGEY BRIN WHO was obsessed with efficiency would find a soul mate in Larry Page. Larry was born in Lansing, Michigan, where his father, Dr. Carl Victor Page, was a professor of computer science and artificial intelligence at Michigan State. His mother, Gloria Page, had a master’s degree in computer science; she taught at the university before becoming a database consultant. With Larry and his older brother, Carl, the Pages lived comfortably in a middle-class neighborhood. By age seven, Larry was proficient on the Exidy Sorcerer computer his dad had brought home, and this ignited his interest in technology, as did the technical magazines and electrical engineering assignments his father also brought home, and his brother Carl’s skill at taking things apart. Larry’s family, like Sergey‘s, welcomed argumentative challenges. The Pages were readers, and Larry fondly remembers vacations to Oregon when they’d take an empty suitcase to fill it with books from the renowned Powell’s Books, in Portland. Unlike Sergey, however, he was conspicuously quiet, and had a bad case of acne. He was a loner, someone who as an adult friends would describe as shy and strangers would describe as asocial. He chose not to follow his mother’s faith, Judaism, but like his father chose not to embrace a religion. Perhaps this was but one reflection of an unsettled home; his parents divorced when he was eight, and his father married a colleague at Michigan State. Carl, nine years older, left home after high school to get a computer science degree. He later was a founder of eGroups.com, an Internet company sold to Yahoo in 2000 for about four hundred million dollars.