It may take far less time than that. Electronic books are popping up everywhere-anything from baseball-trivia collections in the shape of tiny pocket calculators to elaborate $2,000 software c require state-of-the-art desktop computers. Some electronic books are already more popular than their print counterparts. Michael Mellin, Random House’s publisher in charge of electronic books, estimates that the handful of one-volume print encyclopedias introduced since 1990 have sold about 100,000 copies. In that time, consumers have snapped up nearly 400,000 electronic encyclopedias. “We’re not talking about the future,” says Mellin. " This is already happening." So far there is a lot more interest in books you use-reference works-than in books you actually read. But before long, “there will be as many kinds of electronic books as there are conventional books,” says Morton David, CEO of Franklin Electronic Publishers. “Print has had around 500 years to evolve. We’ve only been doing it for a few years.”

Electronic books aren’t just a new place to park your Proust. “You can’t outbook the book just by adding electronics,” says Paul Saffo, an analyst at the Institute for the Future. “Publishers will need to offer something books can’t.” Take the “Expanded Books” series by Voyager in Santa Monica, Calif. These $19.95 titles include Michael Crichton’s “Jurassic Park” and Susan Faludi’s “Backlash.” Delivered on floppy discs, they are meant to be read on the backlit, black-on-white screen of the Apple Macintosh PowerBook. These offerings give a taste of frills to come. Eyes tired? A click of the mouse makes the print four times larger. Want to see every appearance of the word “pig” in Faludi’s “Backlash”? The software searches the entire book automatically. Another nice touch: Faludi’s footnotes can be instantly called up when you reach the appropriate text-no more flipping back and forth.

Novels might benefit from some electronic augmentation, too. Tom Clancy’s “Hunt for Red October” could have been published on discs in several editions, says Bart Faber, a group president with giant printer R.R. Donnelley: one with just plain text, another with maps, submarine blueprints and other toys for the techno-thriller junkie. Or consider Sony’s electronic version of Ira Levin’s novel " Sliver": when you get tired of reading on screen, you can put on headphones and listen to an audio version played from the same disc.

The Voyager books require a full-blown Macintosh computer to run, but the next generation of electronic books may well be single-purpose machines about the size of a paperback. Users will plug in credit-card-size memory chips or compact discs: both can hold vast amounts of information, and the discs can also contain graphics, sound and even video. Sony’s upcoming multimedia Player (sometimes called the Bookman) is not much bigger than a large paperback and has a tiny keyboard, screen and speaker. In the fall, Franklin will introduce an even smaller Digital Book capable of holding two different memory cards. A doctor working in a Spanish-speaking area, for example, could load both a Spanish-English dictionary and a drug handbook into a gadget that fits in a shirt pocket.

On a grander scale, this summer IBM will begin selling schools the tools students need to create their own electronic books. The Illuminated Books and Manuscripts system is pricey-$2,000 for the software and about $8,000 for the souped-up PC-but impressive. It comes with five documents already “illuminated”-each one appears on the computer screen as a printed page, and students can easily order up sound and video presentations to accompany the text. Actors, for example, provide various readings of “Hamlet”; politicians, including Joseph P. Kennedy II and Daniel K. Inouye, discuss the Declaration of Independence. The IBM package also includes an additional 100 books on disc-from the collected Shakespeare to the Bible-ready to be illuminated by the students by attaching their own text, audio and images, linking them all together through the technique called hypertext.

For now, some electronic-book creators remain cautious about just how hyper to make their texts. When every passage can lead to any other passage, the narrative thread can easily be lost. Broderbund stuck to a straightforward narrative with some interactive bells and whistles in its Living Books series (on compact disc for the Macintosh). “Just Grandma and Me,” by Mercer Mayer, is a delightful 12-page story with animation and voice narration. While there are special effects-click on a hole in a tree and a squirrel runs out, rousts a nesting bird, then disappears back into the tree-the narrative is straightforward. John Baker, executive publisher of the project, says, “The most enduring form of content is still the story.”

Perhaps the oddest twist on electronic books comes from science-fiction author William Gibson, who created much of computer-hacker mythology with cyberpunk novels like “Neuromancer” and “Mona Lisa Overdrive.” Gibson nonetheless produced a short prose work in a limited-edition art piece called “Agrippa,” appearing this week for as much as $1,500 a copy. The text can be read on a computer only once; it then encrypts itself into gibberish. Buyers of the pricey work will have to choose whether to read their purchase or save it as an investment. But Gibson expects his hard-core computer fans to crack the code. " I wouldn’t be surprised if it’s all over the computer networks in a year or so. And that will be a pretty interesting way to be published too."

Paper and electronics will doubtless coexist for decades to come. Someday, for example, books may be delivered electronically to bookstores, then printed on demand, one copy at a time. Those who prefer electronic books could have the same text downloaded onto a disc-perhaps even collecting a half-dozen novels and travel guides to take on vacation. Those are people who can afford computers and vacations. If there is a dark side to these new media, it is economic. “People who enjoy reading on a PowerBook are a real elite,” says Denise Caruso, editor of the newsletter Digital Media. “We need to address questions of access by getting these things down to the cost of books.” Don’t hold your breath-the cheapest PowerBooks cost about $1,000 today. On the other hand, some visionaries have predicted a massive democratization of knowledge as thousands of works in electronic form come on line at local libraries. A grand thought indeed: now all we need to do is figure out how to keep the libraries open until that happy day.