This story is excerpted from Valley of Genius, by Adam Fisher. Everyone who has seen The Social Network knows the story of Facebook’s founding. It was at Harvard in the spring semester of 2004. What people tend to forget, however, is that Facebook was only based in Cambridge for a few short months. Back then it was called TheFacebook.com, and it was a college-specific carbon copy of Friendster, a pioneering social network based in Silicon Valley.

Mark Zuckerberg’s knockoff site was a hit on campus, and so he and a few school chums decided to move to Silicon Valley after finals and spend the summer there rolling Facebook out to other colleges, nationwide. The Valley was where the internet action was. Or so they thought.

In Silicon Valley during the mid-aughts the conventional wisdom was that the internet gold rush was largely over. The land had been grabbed. The frontier had been settled. The web had been won. Hell, the boom had gone bust three years earlier. Yet nobody ever bothered to send the memo to Mark Zuckerberg—because at the time, Zuck was a nobody: an ambitious teenaged college student obsessed with the computer underground. He knew his way around computers, but other than that, he was pretty clueless—when he was still at Harvard someone had to explain to him that internet sites like Napster were actually businesses, built by corporations.

But Zuckerberg could hack, and that fateful summer he ended up meeting a few key Silicon Valley players who would end up radically changing the direction of what was, at the time, a company in name only. For this oral history of those critical months back in 2004 and 2005, I interviewed all the key players and talked to a few other figures who had insight into the founding era. What emerged, as you’ll see, is a portrait of a corporate proto-culture that continues to exert an influence on Facebook today. The whole enterprise began as something of a lark, it was an un-corporation, an excuse for a summer of beer pong and code sprints. Indeed, Zuckerberg’s first business cards read, “I’m CEO … bitch.” The brogrammer ’tude was a joke … or was it?