EXPLODING THE PHONE opens with an irresistible hook: In 1967, a secret message planted in the Harvard Crimson leads a curious student to uncover an underground network of "phreaks," phone hackers who figured out how to game the nation's telephone network.

Phil Lapsley's great history of those hackers is packed with schemes, plots, discoveries, and brainy, oddball personalities. From teenagers whistling the right tones to make free long-distance calls to bookies trying to disguise their phone-use patterns, phone phreaking is full of fascinating stories, and in Lapsley's hands they unfold ably alongside a pocket history of the phone system itself.

Many early phone hackers were boys who became enraptured with the phone system at a young age, and a striking number of them were blind. Lapsley doesn't devote much space to wondering why blind kids were so well represented among phreaks, but he does a great job capturing the sense of possibility that a phone could offer to a homebound young boy: "It was more than a playground, it was a laboratory, a place where a little kid could try things out and where he could conduct as many experiments as he wanted. It was a world of possibility, a world prefaced with that most intoxicating of words: if."

The book can feel at times like a series of strung-together magazine profiles of these curious young men, padded with Lapsley's chatty history of the development and details of the nation's telephone infrastructure—the phone company stringing wires from city to city, figuring out how to connect towns and individuals, and eventually enlisting the help of the FBI and law enforcement agencies to control abuses of their network.

Lapsley's writing style is anecdotal, loose, and occasionally a bit silly, like this metaphor that wriggles out of his grasp, in a scene describing an FBI agent swinging a sledgehammer against the door of a bookie's apartment: "At the second blow the door opened. And with it so did a legal can of worms—worms that would, over the next four years, crawl all the way to the Supreme Court." But the history he uncovers—and the questions he poses, about the nature of the relationship between criminality, curiosity, and technology—is compelling, fascinating stuff.