Clearly, the concept will make sense for some kinds of books more than others, says Jared Spool, CEO of User Interface Engineering, a North Andover, MA-based consulting firm. "It makes a lot of sense for a lot of college textbooks to go in this direction, but I'm not sure that a detective novel has a lot to offer there," he says. Delivering such interactivity is a likely new direction for Wikipedia and search engines and many other sources beyond Wolfram Alpha, he points out.

Many online publications are moving in this direction, and "the Wolfram example is a good one" of how to embed interactive graphics and updated information into e-books, says Walter Bender, president of the nonprofit educational software maker Sugar Labs and former president of One Laptop per Child--the philanthropic organization that pioneered the netbook format by inventing the so-called $100 Laptop for children in the developing world.

Bender adds that the trend will ultimately break down journalistic walls by, for example, making it harder to justify not providing source material beyond a few hyperlinks. "A long-standing pet peeve of mine is that most of the material gathered by a journalist during an interview never makes it into the story. It is trivial to include the entirety of an interview in a link. This does not deter the journalist from cherry-picking sound bites, but provides the reader opportunity to dig deeper into the context in which the quote was extracted," Bender wrote in a recent paper.

The Wolfram Alpha engine taps databases that are maintained by Wolfram Research, or licensed from other sources. It deploys an enormous collection formulas and algorithms--already embodied in Wolfram's Mathematica software--to compute answers for searchers. The iPad has been out for almost two months, and launched internationally on Friday.

Spool says that for all the benefits of an expected new tide of e-book interactivity, "the biggest prediction out of developments like The Elements is that nobody is ever going to be productive again," he says. "You are going to start clicking and pointing and rotating and being distracted by 100 cool things."