DARK TERRITORY

For centuries, spies could only listen to enemy communications. In this thoughtful, opinionated history, a Pulitzer Prize–winning journalist warns that in today’s cyberage, “once they hacked a computer, they could prowl the entire network…they could not only read and download scads of information, they could change its contents—disrupt, corrupt, or erase it—and mislead or disorient the officials who relied on it.”

In the 1983 movie, WarGames, a teenager unwittingly hacks into the United States’ defense system, nearly causing World War III. One viewer, an alarmed President Ronald Reagan, commissioned a groundbreaking 1984 directive giving our largest intelligence agency, the National Security Agency, responsibility for securing computer networks. Then the issue basically vanished for a decade. Soviet technology was far behind America’s. In the mid-1990s, teenage hackers broke into American military computers, and a Russian intelligence agency did the same, so the issue was revived. Experts agreed that attack is the best defense, and Slate “War Stories” columnist Kaplan (The Insurgents: David Petraeus and the Plot to Change the American Way of War, 2013, etc.) delivers an eye-opening account of the dawn of cyberwar in 1995, when the air war in Serbia was won through crippling of its air defenses by information warfare. A decade later, the Stuxnet computer worm wreaked havoc on Iran’s nuclear centrifuges, a triumph of digital skulduggery but perhaps an act of war. Though enthusiasts ignore the implications, Kaplan does not. Iranian hackers are inflicting expensive revenge, and a Chinese government agency is devoted to extracting useful information from American computers. Readers may take comfort knowing that we have the capacity to do the same.

An important, disturbing, and gripping history arguing convincingly that, as of 2015, no defense exists against a resourceful cyberattack.