Realistic electronic books

Abstract

We describe a software book model that emulates a range of properties associated with physical books—analog page turning, visual location cues, bookmarks and annotations—and, furthermore, incorporates many advantages of digital environments—hyperlinks, multimedia, full-text search, automatic identification of synonyms, cross-referencing of key terms with an online encyclopedia, and an automatically generated back-of-the-book index. Usability studies were conducted to compare performance using these books for various reading tasks with HTML, PDF and physical books. Participants completed the tasks more efficiently with the new interface without any loss in accuracy; they also preferred it.

Introduction

The electronic book industry is burgeoning. Libraries and other content providers are digitizing documents to allow readers around the world to access them online. The Open Content Alliance and Google are creating collections of tens of millions of volumes accessible through the Internet Archive and Google Books respectively. Manufacturers compete to produce reading devices that are light and mobile, with high resolution displays and many other features—Barnes and Noble's Nook, Amazon's Kindle, and the Sony Reader are typical examples. However, neither the underlying document representation nor interaction with electronic books has evolved significantly—apart from a few superficial visual effects. As a result, although users are increasingly willing to read documents sequentially on-screen, most still prefer to print them when they want to study them intensively (Nicholas et al., 2008, Gorman and Crawford, 1995, Crawford, 1998).

The use of books to store knowledge has a long tradition—books are arguably the most mature user interface ever devised for presenting information. People have acquired a variety of strategies and manipulation techniques, such as using fingers as bookmarks or riffling through pages while browsing (Severinson et al., 1996, Kerr, 1986). Compare a medieval book with a modern one: the same principles are still at work. Readers need only learn these conventions once, and can use them for the rest of their lives.

Current electronic document systems offer great added value over paper books: authors can revise information quickly and incorporate hyperlinks and multimedia, and readers can locate words or phrases through full-text search. However, electronic book applications fail to provide adequate cues about the reader's location in a document, and do not support interactions that are readily achieved with physical books without disrupting the ongoing reading activity (Dillon, 1992, O'Hara and Sellen, 1997, Conklin, 1987, Edwards and Hardman, 1989, McDonald and Stevenson, 1998). These interactions are exactly the features that physical books have evolved to support.

Opinion on the importance of emulating the appearance of printed books in the electronic environment is divided. Some researchers argue that it is unnecessary to paginate documents or maintain their printed page layout (Rowland et al., 1995, Nielsen, 1998, Kol and Schcolnik, 2000, Shneiderman, 1998, McKnight et al., 1991). They believe that with training and practice, users will no longer rely on the book model to locate information. Others contend that users are dissatisfied with digital document systems because they do not embed familiar book metaphors (Benest, 1990, Henke, 1998, Landoni et al., 2000, Crestani and Ntioudis, 2001, Barker et al., 1994). Their studies show that all participants, regardless of computing experience, find the book metaphor easy to use and understand, and that people can utilize their familiarity with paper documents to navigate and obtain information from digital text.

In order to investigate whether digital books can capitalize on reader experience with physical documents to enhance electronic reading, we have developed a software model called Realistic Books that is designed to combine the advantages of physical and electronic documents, and implemented a way of creating such books automatically from any HTML or PDF file. We have also compared performance using the new interface with existing electronic reading interfaces, and with the original physical form itself—the humble book.

Over nearly three decades, researchers have developed various electronic document representations, such as Book Emulator (Benest, 1990), XLibris (Schilit et al., 1998), and 3Book (Card et al., 2004, Card et al., 2004). Most are claimed to have glowing potential, but their proponents rarely make objective empirical comparisons of user behavior and performance with conventional representations. Because these new representations are not available for others to use, we cannot compare their performance with that of Realistic Books, nor with HTML, PDF and physical books.

After defining the scope of the investigation, this paper reviews the historical development of document systems and their effect on reading strategies and behavior, in order to identify, in Section 4, aspects of both printed and electronic documents that might enhance reading performance. Section 5 describes how documents are presented as Realistic Books, and the functions that are supported. Section 6 explains how Wikipedia can be used as an encyclopedic knowledge base to automatically identify key terms and phrases in book text, provide on-demand definitions, and search related pages in the book. Finally, we evaluate system responsiveness and present the results of user studies that compare people's browsing, searching and annotation performance and behavior in simulated books with the HTML, PDF, and physical representations.