Part 1 • About eBooks

Chapter 1 • What are eBooks?

Richard Adams

What are They?

eBooks are electronic books that are designed to be read on tablets, eReaders, and laptop and desktop computers. Similar to web pages, eBooks are written with the eXtensible Hypertext Markup Language (XHTML), styled with Cascading Style Sheets (CSS), and can interact with readers via JavaScript. Depending upon the format, they can contain photos, videos, animations, and a variety of other media.

eBooks can be read on various devices. Low-cost, lightweight, black-and-white devices are referred to as eReaders, such as Amazon’s Kindle, Kobo’s Aura, and Barnes & Noble’s Nook. eBooks can also be read on iPads with eReader apps like Apple’s iBooks and on Android tablets with apps from Amazon, Kobo, Barnes & Noble, and other vendors.

Table 1.1. Advantages and Disadvantages of eBooks
Advantages Disadvantages
  1. Usually low in cost
  2. Weight is that of the tablet or eReader
  3. Can fit multiple eBooks on one device
  4. Can access immediately from internet or eBook store
  1. Can be more difficult to read than ink-on-paper books
  2. Limited screen “real estate” (area)
  3. A small or thin paperback book could be lighter than a tablet
  4. Tablet/eReader could be expensive, risk of loss or damage
  5. Battery, recharging, electrical power

eBook Formats

Reflowable eBook on an Amazon Kindle B&W eReader (photo by Frank Holleman on

ePub Reflowable (RFL). ePub is an open-source eBook format whose standards are controlled by the International Digital Publishing Forum (IDPF,, a division of the World Wide Web Consortium (W3C, ePub can be read on MacOS, Windows, iOS, and Android with a suitable app. The .epub file format is a ZIP-compressed archive that includes pages in XHTML, styles in CSS, JavaScript (if any), and media files for images and videos.

A good theme for reflow able ePub is “text is king.” ePub-RFL is a good format for text-heavy documents that have minimal, if any, illustrations, although color and black-and-white photos and drawings can be added. The font and text size can be chosen by the reader for maximum legibility.

The best way to understand the utility of ePub-RFL is if you see someone with an eReader on the train, bus, or airplane, or waiting in a doctor’s office. Perhaps this person wants to pass the time by reading a novel or enrich themselves with a psychology or business book. These eBooks probably contain mostly text and very few illustrations. The readers can use a lightweight eReader that’s easy to carry around and not very expensive.

ePub-RFL uses XHTML and CSS languages, which allow the content to adapt to different-sized eReaders, tablets, and orientations (e.g., vertical or portrait, horizontal or landscape).

Cookbook content suitable for ePub-FXL. (Photo courtesy of Instant Pot Eats on Google Images.)

ePub Fixed-Layout (FXL). Fixed-layout ePub is a version of ePub with fixed page sizes and elements. An appropriate theme for ePub-FXL may be “media is king.” Unlike ePub-RFL, the text in ePub-FXL does not reflow based on the tablet, screen size, orientation, and user preferences for type. This format is useful when the author wants to set a fixed relationship between text and photos or media. Examples include recipe books and children’s books.

ePub-FXL allows the use of a wider range of media, including grouped photos and captions, animations, videos, and audio files. A common use of this format is for children’s books in which the text is linked to an audio file so the reader can hear the text read out loud.

Mobi. An abbreviation for Mobipocket, Mobi is a proprietary format of ePub developed by Amazon for display on its Kindle eReaders. Mobi is most appropriate for B&W documents that are mostly text, although the popular Kindle and Kindle Paper White devices do support shades of gray.

iBooks. These are Apple’s proprietary format of ePub developed for the iPad devices. iBooks can be created only on MacOS computers using the free iBooks Author page layout program. An advantage of iBooks is the extent and variety of media that they support, including not only photos, videos, and animations but also image galleries, animated panoramic views, 360° objects, and embedded web sites.

Table 2-1. eBook Formats
Format Create with Read on Comments
ePub RFL (reflowable) Adobe InDesign, Apple Pages, PressBooks iPad, Android tablet; Mac, Windows computer Reflowable format provides flexibility for text-heavy documents
ePub FXL (fixed-layout) Adobe InDesign, Apple Pages iPad, Android, MacOS, Windows Fixed layout good for grouped photos and text, e.g., kids’ books, recipe books
Mobi ePub with file converter, PressBooks Amazon Kindle Proprietary form of ePub, good for text-heavy documents in B&W
iBooks Apple iBooks Author iPad, Mac computer Proprietary form of ePub with media-rich envt.


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eBook on eBooks by Richard Adams is licensed under a Creative Commons Attribution 4.0 International License, except where otherwise noted.

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