Of the various branches of U.S. statecraft, intelligence is unique for its combination of influence and obscurity. As Amy Zegart notes in her new book Spies, Lies, and Algorithms, American colleges have more courses on rock music than on espionage. Zegart manages both to give an educational overview of American intelligence and show precisely how sorely policymakers need that education. Like the general public, congressmen have only the foggiest notion of how the CIA or NSA work — their views of the intelligence field are more likely to come from Bond or Bourne than from real life.

Spies, Lies, and Algorithms is a primer and reads like it. Most of it is structured like an introductory textbook, proceeding from questions such as “what is counterintelligence?” to concise passages that explain the basics. Zegart’s pedagogical style sometimes leads her to state the obvious — for example, no one should need to be told that intelligence isn’t policymaking. Yet if some of her chapters seem rather basic, it’s with good reason. Her hand-holding is merited by the fact that her intended audience in Congress knows next to nothing about U.S. intelligence: Competent politicians, as H.L. Mencken remarked, are as rare as honest burglars.