“The founders of start-ups as varied as YouTube, Palantir Technologies, and Yelp all worked at PayPal. Another set of people—including Reid Hoffman, Thiel, and Botha—emerged as some of the technology industry’s top investors. PayPal staff pioneered techniques in fighting online fraud that have formed the basis of software used by the CIA and FBI to track terrorists and of software used by the world’s largest banks to combat crime. This collection of super-bright employees has become known as the PayPal Mafia—more or less the current ruling class of Silicon Valley—and Musk is its most famous and successful member.”