From Publishing Frontier, a description of precisely the kind of "reading" I imagined for works of non-fiction. In this quote, the blogger, John Warren, is imagining an e-version of Barry Cunliffe's amazing Europe Between the Oceans:
Clicking on the place-name of Tyre deploys Google Earth. Maps of migrations or empires, instead of static, depict the spread and flow over time. Instead of a single picture depicting the ancient city of Miletos, or a bronze warrior god from the 12th century, a gallery of photos is embedded in the e-text. Links lead to further scholarship or modules about topics of particular interest to the reader.
I concur, by the way, with with his praise for Cunliffe's book, both its content and its physical appearance. (And that it's heavy as hell. Hard to curl up with it, it weighs so much!) Amazing piece of scholarship and book-making.