Larry thought Sergey was arrogant. Sergey thought Larry was obnoxious. But their obsession with backlinks just might be the start of something big.

It began with an argument. When he first met Larry Page in the summer of 1995, Sergey Brin was a second-year grad student in the computer science department at Stanford University. Gregarious by nature, Brin had volunteered as a guide of sorts for potential first-years - students who had been admitted, but were still deciding whether to attend. His duties included showing recruits the campus and leading a tour of nearby San Francisco. Page, an engineering major from the University of Michigan, ended up in Brin's group.

It was hardly love at first sight. Walking up and down the city's hills that day, the two clashed incessantly, debating, among other things, the value of various approaches to urban planning. "Sergey is pretty social; he likes meeting people," Page recalls, contrasting that quality with his own reticence. "I thought he was pretty obnoxious. He had really strong opinions about things, and I guess I did, too."

"We both found each other obnoxious," Brin counters when I tell him of Page's response. "But we say it a little bit jokingly. Obviously we spent a lot of time talking to each other, so there was something there. We had a kind of bantering thing going." Page and Brin may have clashed, but they were clearly drawn together - two swords sharpening one another.

When Page showed up at Stanford a few months later, he selected human-computer interaction pioneer Terry Winograd as his adviser. Soon thereafter he began searching for a topic for his doctoral thesis. It was an important decision. As Page had learned from his father, a computer science professor at Michigan State, a dissertation can frame one's entire academic career. He kicked around 10 or so intriguing ideas, but found himself attracted to the burgeoning World Wide Web.

Page didn't start out looking for a better way to search the Web. Despite the fact that Stanford alumni were getting rich founding Internet companies, Page found the Web interesting primarily for its mathematical characteristics. Each computer was a node, and each link on a Web page was a connection between nodes - a classic graph structure. "Computer scientists love graphs," Page tells me. The World Wide Web, Page theorized, may have been the largest graph ever created, and it was growing at a breakneck pace. Many useful insights lurked in its vertices, awaiting discovery by inquiring graduate students. Winograd agreed, and Page set about pondering the link structure of the Web ...