Disney's Digital Books also suggest the potential of children's appbooks on an iPad. The two Toy Story appbooks capture the marvelous aspects of richly illustrated children's books along with features only possible with a computer. The pages are animated and can play music in the background, but the effects are gentle, so they don't turn the book into a video.

With a tap, a child can turn on the "read to me" feature and a narrator reads through the text as each word on the page is highlighted. This not only makes Disney appbooks engaging for a child who can't read and doesn't have an adult readily available; it also suggests the possibility that some children will follow the highlighted words as the narrator talks. From that synchronized reading and listening, children can learn to link written and spoken words. If more publishers jump on this bandwagon, the educational potential of self-paced, narrated and interactive appbooks is enormous.  Another endearing aspect of the "read to me" feature is that every page can have a custom reading recorded on the iPad's built in microphone. Thus a parent can easily record his or her voice reading the book and allow a child to listen to the narration even when the adult is away.

Not all of the appbook experiments are successful. A company called Vook has released several offerings that mix text with video. Their Brothers Grimm Fairy Tales appbook was ugly, and the embedded video added little to the experience of enjoying a classic fairy tale. Even at $0.99, I felt I'd wasted my money. 

The better appbooks are reminiscent of the now forgotten heyday of CD-ROM books in the mid-1990s that first combined text with a then newfangled thing called "multimedia." Voyager, the standout of this short-lived medium, produced high-quality titles like a Companion to Beethoven's Symphony No. 9. Voyager's release of the CD-ROM for A Hard Day's Night was described as "a coffee table book with the movie attached." Though the era of smart CD-ROM publishing died in the late 1990s with the growth of the Web, little online since then has matched the quality, interactivity and rich integration of multiple media available in the best CD-ROMs.

The promise of appbooks is that a new generation of interactive books has arrived. Unlike the CD-ROM era in which publishers struggled to gain sufficient distribution, now every appbook has a ready market through Apple's App Store, and, with time, Google's App Marketplace and others. Moreover, the technology to enjoy compelling interactive books is now relatively easy and affordable. While neither The Elements nor the Disney titles are perfect, they literally speak to how books and reading can be supplemented in ways that were never before possible.