In the early days of Facebook, Zuck kept his plans for world domination in handwritten journals. He destroyed them. But a few revealing pages survived.

In a journal with unlined 8-by-10 paper, he sketched his mission and product design and explored how a tiny company might become a vital utility for the world. In detail, he described features called Open Registration and Feed, two products that would supercharge his company.

Zuckerberg found focus in that notebook and others. In his jottings are the seeds of what would come—all the greatness and the failings of Facebook. Over the next 10 years, Zucker­berg would execute the plans he drew up there. Facebook would transform itself from a college student hangout to the dominant social media service, with a population bigger than that of any country in the world, and was on its way to having more members than any religion