According to Wright, print and conventional e-books are limited to "...two layers: the main body and a thin stratum of footnotes and endnotes." He uses the eeb format to add multiple narratives that readers can select among, allowing him to address varying audiences with the same publication. Wright compares the design, actually, to that of Daniel Bomberg's 1523 design for Talmud editions, with a running source text at the center, with an array of commentaries surrounding it.
Wright comments that the opportunity thus opens up for academics to appeal in a single publication to scholars in their own discipline, explaining in full detail how they researched and came to their conclusions. But at the same time, they can appeal to non-specialists who may be interested in the topic on a less technical level. For instance, he mentions the ability to include links to maps, video clips, images as well as icons leading specialists to lengthy quotes from sources that would be unpalatable to lay readers. While scholars like footnotes for ease of consultation, publishers prefer endnotes to avoid breaking up the flow of text and intimidating potential readers. Icons or links to references avoid the debate, and please both parties. An author can include as many references, in as much detail as needed for the scholars, without distracting or driving away the non-professional crowd. References appear in a window which can be scrolled. If you go to the online version of the Chronicle article, in particular, you can see some very beautiful illustrations and interesting in-sets from this book, which give you an appreciation for what Wright has added, visually, at least to the text. I have to say, though, that some parts of the illustrations for this article reminded me a bit of Encarta...
The end of the article includes a brief survey and review by Wright of his own efforts to find a program to build an enhanced e-book. He settled on the free app from Apple, iBooks Author. It is a very interesting and exciting article, not least because Wright really opens up the idea of what an enhanced e-book might be.
If you use iBooks Author, be careful of the license - I pulled up an Information Week article from 2012 complaining about the iBook Author license, and warning that Apple claims the sole right to sell any publications created with their free software unless they give a written authorization otherwise. This may have changed since it is apparent that Wright's book is being published by Cambridge University Press. Or the press and author may have negotiated a written agreement with Apple at the beginning of their work. In February, 2012, Apple clarified this to explain that only materials published with the .ibooks suffix are covered by this claim. If you publish as a .text or .pdf file, that EULA clause does not affect you.
Here is an article about enhanced e-books with a handy review of several platforms for creating enhanced e-books. It seems quite apparent that the Apple is by far the best and most robust. The article also is helpful in thinking about the various enhancements that are available and what is and is not a real enhancement. When you look at a Publisher's Weekly article from a year ago about Harper Collins' EEB collection, you can begin to understand why the tradebook EEBs have not been big successes. They added video interviews of an author, and audio excerpts. To me that does not seem like it is reaching the potential of the format at all! It is possible that trade books just are not the right area for enhanced e-books, and that until you get to a scholarly publication with the possibility of becoming a cross-over book of interest to a wider public, there is not a real application. Does anybody remember a year or two ago when they brought out this e-book, Chopsticks? That actually seems to have been fairly successful, though I don't know that it's been duplicated with another successful EEB tradebook. Anybody know?
The image decorating this post is from Wright's book on King David, reproduced from the Chronicle. article.