Then he saw how Goldberg's students incorporated the vocabulary of bookmaking into multimedia cover layouts. Rather than borrow techniques from documentary film, they used typography in more sophisticated ways that seemed to be digitally-native expressions of book design. Her students also used moving images, video, and audio.

The digital book can be a complete piece of art, Goldberg explained, though "we're doing it by the seat of our pants. There is no technology that is uniform yet." And publishers haven't embraced it, she says, because "they don't have resources."

"I don't think anybody's figured out how to create a whole creative environment that's able to fit well into every publishing house right now," Goldberg told me, adding, "I'm sure there are companies that are talking about it all the time. But I haven't seen anybody go about it."

Himmel's call after her talk came as a sign of hope. He asked Goldberg for her students' phone numbers. He isn't quite sure how he wants to put them to work, but he described "a kind of laboratory" to develop some prototypes using the most accessible software. There's the ubiquitous program, Adobe—which Goldberg and others say can be hard to use for digital book design—and Himmel pointed to Apple's iBook platform as an alternative option. Still, Himmel says, this is all very new.

And costly. Paul Buckley, Vice President, Executive Creative Director at Penguin—who oversees the development of 800 book covers each year—noted the expense of adding digital features: "Benefits have not yet caught up to the costs of this extra content. Because the viewer's not going to pay for it." Publishers' art departments haven't traditionally come equipped with highly tech-savvy illustrators and typographers. And even as more digitally-capable designers arrive, so too will their demand for new tools to support their talents.

With or without digital frills, the cover sensibility is fetching simplicity. A winning formula tends to involve bold text and pared down illustrations. Says Buckley, "We need to broadcast ourselves clearly."

Legible means, literally, capable of being read. For Buckley and other like-minded designers, there is elegance in legibility: The cover can be deciphered by the human eye, from a distance or on a small screen. But it's not only our eyes that must do the reading. So too, computers read our books, with varying degrees of success. So says Holladay Penick—Creative Director at OnixSuite, and formerly of the Institute for the Future of the Book—in noting that "legibility is a big concern."

When Buckley's team at Penguin designs a book cover, they turn it into a PDF (or sometimes a JPG) and load it onto their server for someone else to send out into the marketplace. But major retailers, like Apple's iBook store, won't sell ebooks as PDFs, mainly because these files can't adapt to different screen sizes. Instead, publishers must offer up their books in a format called EPUB, sometimes by working backwards and converting from the PDF. The EPUB file can then be changed again, as is the case for Amazon's Kindle. In other words, digital reading doesn't only have one kind of digital expression, and this poses obvious complications for how books may be aesthetically packaged.