At Large: The Strange Case of the World's Biggest Internet Invasion.

In 1983, the movie War Games catapulted Matthew Broderick to stardom. It also added the phrase "computer hacker" to the American lexicon. The tale of a bright high school student who brings the world perilously close to World War III by breaking into a secret military computer, War Games opened new vistas for adolescent misbehavior and inspired a generation of suburban nerds to cruise the Net in search of similar adventure.

Fourteen years later the stories that have emerged are no longer fictional. Clifford Stoll's The Cuckoo's Egg, Michelle Slatella and Joshua Quittner's Masters of Destruction, and Cyberpunk, which I co-authored with Katie Hafner, all explore the brave new world of young men obsessed with powerful machines and computer networks.

Now in At Large: The Strange Case of the World's Biggest Internet Invasion, David H. Freedman and Charles C. Mann add the story of an odd young fellow whose life is consumed by the desire to systematically break into thousands of computers via the Internet. Once inside, he doesn't appear to do very much; he looks for software, reads other people's e-mail and generally uses each new computer to leapfrog to the next one.

Unfortunately, the authors offer little insight into the man they call Matt Singer (his real name is not revealed, presumably because he has never been arrested). We learn that he is a troubled individual who has spent time in an Oregon mental hospital. But by the end of At Large, Matt Singer is still largely a cipher. It appears that while the authors have spoken to members of Singer's family, they have not directly inter-viewed him in any depth. That's a shame, because Singer's behavior resembles that of many other computer criminals -- like Kevin Mitnick, for example, a notorious computer outlaw who was arrested more than six times over the course of 15 years. An examination of what makes Singer tick could have given us a better understanding of computer outlaws in general.

One thing Freedman and Mann do well is to demonstrate how the rapid evolution of electronic crime has left law enforcement choking in dust. For example, despite the fact that it knew Singer's identity and location, the F.B.I. flailed for months and ultimately failed to arrest him. But the reader never feels outraged by the government's ineptness because Freedman and Mann offer such a benign view of Singer's crimes. Inside the computer underground, theft is usually justified by arguing that nothing was taken. The argument is that stealing software or illicitly looking through someone's e-mail is OK, because these electronic bits have not been taken away from their original owners. While they don't exactly endorse this view, the authors leave the reader with the disarming sense that Singer did little real damage.

In fact, by stealing e-mail and software from the computer security community during his four-year electronic joyride, Singer helped undermine the general safety of the Internet. He may also have compromised national security. The authors say Singer frequently traded information with a mysterious young Israeli who is identified only by the initials "JSZ." But what they don't mention is that JSZ is target of an ongoing investigation by United States counterintelligence officials.

The lack of computer security that this book does such a good job of describing is a cause for serious concern -- particularly as the Internet continues to carry more and more of the world's commerce. Although the Matt Singers of the world may have no intention to "rob" in the Willie Sutton sense of the word, the information they trade in the computer underground is remarkably useful to those who are motivated by more conventional criminal values.