Spying has never been more ubiquitous-or less understood. The world is drowning in spy movies, TV shows, and novels, but universities offer more courses on rock and roll than on the CIA and there are more congressional experts on powdered milk than espionage. This crisis in intelligence education is distorting public opinion, fueling conspiracy theories, and hurting intelligence policy. In Spies, Lies, and Algorithms, Amy Zegart separates fact from fiction as she offers an engaging and enlightening account of the past, present, and future of American espionage as it faces a revolution driven by digital technology. Drawing on decades of research and hundreds of interviews with intelligence officials, Zegart provides a history of US espionage, from George Washington's Revolutionary War spies to today's spy satellites; examines how fictional spies are influencing real officials; gives an overview of intelligence basics and life inside America's intelligence agencies; explains the deadly cognitive biases that can mislead analysts; and explores the vexed issues of traitors, covert action, and congressional oversight. Most of all, Zegart describes how technology is empowering new enemies and opportunities, and creating powerful new players, such as private citizens who are successfully tracking nuclear threats using little more than Google Earth.