An electronic textbook can be (1) a simple electronic version of a print book, or (2) a print book enhanced with extra elements (additional contents, multimedia animation, data/code files, etc.), or (3) a redesigned "document" that exploits various possibilities of the digital device, e.g. advanced hypertext navigation.
See also:
Source formats:
Delivery formats:
See also: the Document standard article
Simple electronic textbooks that are just versions of a print book or the other way round, can be produced using either a "single source authoring method" or through the use of so-called filters. The best single source authoring technologies rely on structured authoring. E.g. publishers like O'Reilly strongly encourage authors to use DocBook. IBM sponsors on-demand publication using DITA.
A less good solution is using an unstructured format like Word or a Mediawiki (read the Wiki book article) and then use translation filters.
Currently (April 2012), most electronic textbooks are simple electronic version a print book. Electronic media have a really bad screen resolution (even the most expensive devices such as high-end CAD laptops) and they don't have an easy transportable built-in annotation mechanism. Therefore reading and navigation is cumbersome and rather painful. According to Woody (2010), adding some extra features to e-books doesn't make a difference.
“Students do not prefer e-books over textbooks regardless of their gender, computer use or comfort with computers. No significant correlations existed between the number of e-books previously used and overall preference of e-books: Participants who had previously used an e-book still preferred print texts for learning. Despite the ability to easily access supplemental content through e-books via hyperlinks and other features, students were more likely to use special features in print books than in e-books.” (Woody et al. 2010).
“[...]The strong visual and interactive elements in e-books that are commonly touted as strengths of e-books do not seem to be used to their potential by this sample and, in fact, may be used less in e-books than in textbooks as currently designed. Based on these results, we argue that at this time the medium itself may not be as comfortable as a textbook experience for readers and that the design of an e-book may need to differ from that of a textbook to make for a more constructive user experience.” (Woody et al. 2010).
This type of research doesn't imply that the use of e-books in education is counter-productive. When e-books are used for reference, e.g. students only will read (and maybe print) selected sections, e-books are a good cost-effective alternative with respect to ordering many books for the library that may or may not be used. Of course free e-books are interesting, since many students can't afford to buy text books or to print e-books. See Open educational resources.
In addition, it is easier for a teacher to create custom-made "e-books" from various sources. Also, we believe that e-books are ideally suited for reference books, i.e. devices that support more project-oriented learning
(http://www.sciencedirect.com/science/article/pii/S0360131510001120)