When Larry and Sergey first met, they didn’t like each other much.

In the summer of 1995, Larry Page was considering a transfer to Stanford University’s graduate program in Computer Science. Sergey Brin was already two years into the program, and he had signed up to be a tour guide of sorts to potential students. One summer day he showed Page and a group of other potential Stanford students around the Bay Area.

“I thought he was pretty obnoxious,” Page said later of his guide. “He had really strong opinions about things and I guess I did, too.”

“We both found each other obnoxious,” Brin agrees. And yet, it wasn’t hatred, exactly, as much as it was the coming together of two strong, fiercely proud intellects. They might have stepped on each other’s toes a bit, but at the same time there was a degree of frisson to the encounter. “We spent a lot of time talking to each other,” Brin would recall, “so there was something there. We had a kind of bantering thing going.”

On the surface, it might not have seemed like Page and Brin had anything in common. Page was Midwestern, born in East Lansing, Michigan on March 26, 1973. Brin was born in Moscow, in the iron-curtain-era USSR, on August 21, 1973, only emigrating to the United States when he was six years old. Page was reserved, quiet, contemplative. Brin was outgoing, gregarious, loud. Page was a deep thinker, a visionary. Brin, a problem solver, an engineer’s engineer.

But the two had more in common than anyone knew that first day. For one thing, they both came from academic families. Page’s father was a pioneering Computer Science professor at Michigan State University, where his mother was also a computer programming instructor. Brin’s father was a mathematics professor at the University of Maryland and his mother a researcher at NASA’s Goddard Space Flight Center. Larry and Sergey both grew up to respect research, academic study, mathematics and, especially, computers. And it turned out they both had inquisitive minds that believed in the power of knowledge to overcome any obstacle, intellectual or practical. Each had been inculcated into this spirit of intellectual fearlessness at a young age.

LarryAndSergey

“You can’t understand Google,” early Google employee Marissa Mayer has insisted, “unless you know that both Larry and Sergey were Montessori kids. It’s really ingrained in their personalities. To ask their own questions, do their own things. Do something because it makes sense, not because some authority figure told you. In a Montessori school, you go paint because you have something to express or you just want to do it that afternoon, not because the teacher said so. This is baked into how Larry and Sergey approach problems. They’re always asking, why should it be like that? It’s the way their brains were programmed early on.”

For Larry and Sergey, their intellectual fearlessness overlapped in such a way that their conflicting personalities actually ended up complimenting each other. When Page joined Stanford for the 95/96 academic year, he and Brin became close. Friends took to calling the duo LerryandSergey, suggesting they were somewhat inseparable. The pair would end up debating endlessly on topics ranging from philosophy to computing to films, two equally-matched polymaths thrilling to the intellectual joust. Brin’s hobby project was creating a software program that could provide movie recommendations based on the tastes and viewing habits of other people who had seen similar films (sounds not unlike what Netflix later perfected). Page’s dream obsession was creating a system of networked, autonomous cars to ferry people around (so it’s probably no coincidence that Google is working on driverless cars today).

Even though they were the same age, Brin was academically two years ahead of Page because he had completed his undergraduate Computer Science degree at age 19 and had aced all of Stanford’s required doctoral program exams on the first try. But despite this head start, and despite being the recipient of a Nation Science Foundation fellowship which allowed him to do basically anything he wanted, Brin had stalled out in his quest to nail down a dissertation topic. Of course, the newly arrived Page also needed to decide on his dissertation, and so fate pushed the pair even closer together.

In January of 1996, LarryandSergey ended up working in the same office, number 360 in the just-completed William Gates Computer Science building on Stanford’s campus. The building was of course named after the founder of Microsoft, who had donated $6 million dollars to the construction. All his career, Gates repeatedly predicted that one day, some student somewhere would found a company that would challenge Microsoft for dominance of the tech industry. His prediction turned out to be right, and that company would come from two students working in a building with his name on it.

The web had been a watershed for computer scientists, data scientists, information scientists, mathematicians—the list is endless. For any number of fields, the web was an incredible boon, just from a research perspective. For a wide range of disciplines, the web now presented billions upon billions of datapoints for their research—all available and accessible for free—a corpus of information that was seemingly infinite. Larry Page turned to the web to find a dissertation not because he wanted to build a search engine but because, for a mathematically-inclined computer science graduate student, the web was where it was at in 1996.

Page was struck by a fundamental truth about the web that is glaringly obvious when you state it out loud: it is built on links. One page linking to another; one idea linking to another. But what occurred to Larry Page was that, as of yet, no one had bothered to analyze the structure of the link ecosystem in a comprehensive way. For example, it was possible to know that webpage A linked to webpage B because you could see it… you could follow the link. But what about the reverse? What pages had linked webpage A? There was no way to know. You couldn’t follow a link stream backwards, only forwards. It seems a trivial matter to consider, but Page wondered: if you analyzed all of the back links, if you mapped out the link structure of the entire web, what sort of insight might that data give you? Page’s intuition was that this might be more than just an interesting theoretical question.

As he mulled over the idea with Brin, their shared upbringing as the children of academics kicked in. LarryandSergey knew the power of the academic citation. Their parents had published academic papers. They, themselves, intended to publish academic papers in order to earn their PHDs. And they knew that any academic paper worth its salt built its argument by citing other academic papers and studies. In the world of academia, those citations, the accumulated number of “votes” from paper to paper served to, over the years, to accrue value to given ideas—to essentially rank them based on the number of citations. The most cited papers were understood to be the most authoritative. “It turns out, people who win the Nobel Prize have citations from 10,000 different papers,” Page would say later.

Well, what was a web link but a digital citation? If you analyzed the links, analyzed the citations, you might be able to make inferences about the relative value of a given web page, and possibly even determine which web page was more authoritative by analyzing the back-links in the same way that counting the citations told you which academic paper was the definitive one.

Larry Page wanted to map out the value of the web’s connections by going backward through the link chain. Page went to his academic advisor, Terry Winograd, and asked for the money and machines that would allow him to map the web’s links. He dubbed the project BackRub. When asked how much of the web he intended to map, he replied: “the whole web.”

BackRub/PageRank

“In a sense, the web is this: anyone can annotate anything very easily just by linking to it,” Page would say later. “It seemed kind of cool to gather all the links on the web and reverse them.”

So, in March of 1996, Larry Page launched BackRub by sending search bots, known as “spiders,” out into the web to find all the links. He started with a si...