In 2009, a group of digital technology experts at the Citizen Lab uncovered an espionage network affecting more than 100 countries and targeting ministries of foreign affairs, embassies, international organizations, and media outlets. The investigation was but one example of a contest for the future of cyberspace that was becoming more intense with each passing year. Drawing on the first-hand experiences of the Citizen Lab, Ronald Deibert examines the multiplying forms of control hidden deep beneath the surface of the Net; the lucrative and ominous business of Big Data; and the powerful influence of the next billion Digital Natives, and in doing so poses urgent questions about privacy, democracy, and security. Compelling and timely, and including new commentary on the National Security Agency revelations, Black Code is a wakeup call to everyone who has come to take the Internet for granted.