By DAVID POGUE

CODE

And Other Laws of Cyberspace.

By Lawrence Lessig.

297 pp. New York:

Basic Books. $30.



ntil 1991, the global network now called the Internet was a government project, designed for use by scientists and the military. Then, when the cold war ebbed, the government threw the Internet's doors open to the public and commercial traffic. The government kicked the hatchling out of its nest and then, for the most part, left it alone.

The fact that the Internet is now apparently unregulated is one of its most provocative aspects. Many libertarians, teenagers and hate-crime mongers adore the anonymity and global reach of the Internet: they find it the ultimate forum for free speech. Many parents, legislators and repressive governments fear the Internet for the same reason.

In ''Code,'' the Harvard Law School professor Lawrence Lessig, freshly famous from his role as friend of the court in the Microsoft antitrust suit, makes an alarming and impassioned claim: that the Internet will indeed soon be regulated. ''Left to itself,'' he says, ''cyberspace will become a perfect tool of control'' -- not by the government, which he characterizes as clueless and inadequate, but by software programmers. In a book that's sometimes as brilliant as the best teacher you ever had, sometimes as pretentious as a deconstructionists' conference, Lessig plays digital Cassandra: he predicts that the Internet will become a monster that tracks our every move, but that nobody will heed his warning.

On the way to his conclusion that ''we will watch as important aspects of privacy and free speech are erased,'' Lessig brings a keen focus to some of the thorniest issues posed by today's Internet: free speech, pornography, intellectual property, encryption, law beyond our borders and the courts' inability to stretch the Constitution's intentions to cover the new electronic world. When analyzing these individual trouble spots, the author reveals himself to be a deep, lucid and well-read thinker.

For example, if you're concerned that the Internet makes it too easy to steal intellectual property, he says, you're worrying up the wrong tree -- in fact, ''the lesson in the future will be that copyright is protected far too well.'' By that he means that password-driven software could someday demand payment for every individual reader action -- copying a paragraph, reading something more than once -- and that such modern-day freebies as browsing or quoting from online works will be eliminated.

BOOK EXCERPT

"I taught in Central Europe during the summers of the early 1990s; I witnessed the transformation in attitudes about communism . . . And so I felt a bit of déjà vu when in the spring of 1995, I began to teach the law of cyberspace, and saw in my students these very same post-communist thoughts about freedom and government. Even at Yale -- not known for libertarian passions -- the students seemed drunk with what James Boyle would later call the 'libertarian gotcha': no government could survive without the Internet's riches, yet no government could control what went on there. Real-space governments would become as pathetic as the last Communist regimes. It was the withering of the state that Marx had promised, jolted out of existence by trillions of gigabytes flashing across the ether of cyberspace. Cyberspace, the story went, could only be free. Freedom was its nature." -- from the first chapter of 'Code'

These discussions are thoughtful and measured, but the premise that frames them all is shaky; Lessig doesn't offer much proof that a Soviet-style loss of privacy and freedom is on its way. For instance, the book opens with four cyber-horror stories, each of which illustrates ''a theme that recurs throughout the book'': a state whose antigambling law is circumvented by Web sites in other states, a secret government virus that snoops on your hard drive and so on. But three of the stories are hypothetical (including a silly one involving made-up characters in an online computer game). Where are the real-world examples? Lessig hints that ''architectures of control are possible; they could be added to the Internet that we know.'' Well, of course they could be, but will they be?

Meanwhile, for every software-created problem the author foresees, he can't stop himself from proposing an elegant software-based solution. Can't trust what you read online? Let readers rate the online reporters, much as they can rate books on Amazon.com. Don't want to tell Web sites too much about yourself? Then use P3P (Platform for Privacy Preferences), a proposed software option that would let you control how much personal information is transmitted. How can a state prevent citizens from breaking local laws by using Web sites elsewhere? Enable Web sites to read a digital ID tag that identifies your location. (Such digital ID's, a recurring theme in Lessig's lectures, would also neatly solve the kids-viewing-pornography problem.)

''Code'' is written by an erudite lawyer, academic and computer geek, and unless you too are a lawyer, academic and geek, don't expect uniform clarity. Lessig describes ''a router product that would enable an I.S.P. to encrypt Internet traffic at the link level -- between gateways,'' but doesn't decipher the terminology for the nonnetwork administrator. He's fond of quoting fellow academics, but fails to identify their qualifications or institutions; we're expected to recognize them by their names alone. Most of Lessig's legal discourses are enlightening, but he occasionally forgets those of us who never went to law school: ''A constraint may be objectively ex post, but experienced subjectively ex ante.''

Lessig is also too fond of the coincidence that both law and software are sometimes called ''code.'' To reinforce the cleverness of his title, he uses ''code'' whenever he means ''software,'' making many of his arguments confusing and requiring him to coin the cute but clumsy terms ''East Coast Code'' (law) and ''West Coast Code'' (software).

Lessig's challenging prose isn't just something to whine about, either. It hobbles the book's mission: whipping the public into action. (''Do-nothingism is not an answer,'' he writes; ''something can and should be done.'') But by filling his prose with the language of academia -- is-ism,'' ''distinct modality of regulation'' and so on -- Lessig ensures that his entreaties won't reach the largest possible audience. (Nor does he suggest how his followers should rise up. Writing a letter to Microsoft's programmers, one guesses, probably won't do the trick.)

In the end, Lessig's favorite phrase, ''Code is law,'' is too pat. As he points out, code (software) may indeed restrict behavior -- America Online's chat rooms are designed to hold at most 23 people, so that members can't orchestrate a revolt -- but that doesn't make it law. Unlike actual law, Internet software has no capacity to punish. It doesn't affect people who aren't online (and only a tiny minority of the world population is). And if you don't like the Internet's system, you can always flip off the modem.