When McKenzie Wark wrote Gamer Theory, an analysis of why people enjoy playing video games, Harvard University Press published it as a conventional hardcover. But Wark also put it online using CommentPress. The free blog theme blew the book open into a series of conversations; every paragraph could spawn its own discussion forum for readers.

Sure enough, hundreds dove in, and pretty soon Gamer Theory had sparked erudite exchanges on everything from Plato's cave to Schopenhauer's ideas on boredom. It felt as much like a rangy, excited Twitter conversation as it did a book. "It was all because we opened it up and gave readers a way to interact with each other," Wark says. "It changed the way they read the book."

Books are the last bastion of the old business model, the only major medium that still hasn't embraced the digital age. Publishers and author advocates have generally refused to put books online for fear the content will be Napsterized. And you can understand their terror, because the publishing industry is in big financial trouble, rife with layoffs and restructurings. Literary pundits are fretting: Can books survive in this Facebooked, ADD, multichannel universe?

To which I reply: Sure they can. But only if publishers adopt Wark's perspective and provide new ways for people to encounter the written word. We need to stop thinking about the future of publishing and think instead about the future of reading.

Every other form of media that's gone digital has been transformed by its audience. Whenever a newspaper story or TV clip or blog post or white paper goes online, readers and viewers begin commenting about it on blogs, snipping their favorite sections, passing them along. The only reason the same thing doesn't happen to books is that they're locked into ink on paper.

Release them, and you release the crowd. BookGlutton, a site that launched last year, has put 1,660 books online and created tools that let readers form groups to discuss their favorite titles. Meanwhile, Bob Stein, an e-publishing veteran from the CD-ROM days, put Doris Lessing's Golden Notebook online with an elegant commenting system and hired seven writers to collaboratively read it.

Neither move should come as a surprise. Books have a centuries-old tradition of annotation and commentary, ranging from the Talmud and scholarly criticism to book clubs and marginalia. Stein believes that if books were set free digitally, it could produce a class of "professional readers," people so insightful that you'd pay to download their footnotes. Sound unlikely? It already exists in the real world. Microsoft researcher Cathy Marshall has found that university students carefully study used textbooks before buying them, because they want to acquire the smartest notes.

The technology is here. Book nerds are now working on XML-like markup languages that would allow for really terrific linking and mashups. Imagine a world where there's a URL for every chapter and paragraph in a book—every sentence, even. Readers could point to their favorite sections in a social networking update or instant message or respond to an argument by copiously linking to the smartest passages in a recent bestseller.

This would massively improve what bibliophiles call "book discovery." You're far more likely to hear about a book if a friend has highlighted a couple brilliant sentences in a Facebook update—and if you hear about it, you're far more likely to buy it in print. Yes, in actual print. The few authors who have experimented with giving away digital copies (mostly in sci-fi) have found that they end up selling more print copies, because their books are discovered by more people.

I'm not suggesting that books need always be social. One of the chief pleasures of a book is mental solitude, that deep, quiet focus on an author's thoughts—and your own. That's not going away. But books have been held hostage offline for far too long. Taking them digital will unlock their real hidden value: the readers.

Send a letter to the editor about this story.