EPUB (which stands for Electronic Publication) is today’s eBook standard format. EPUB was developed by the IDPF (International Digital Publishing Forum). EPUB files always have the ending (surprise!) .epub. e-Readers usually read .epub files.
An EPUB file is, for all practical purposes, a mini web site and EPUB e-Readers “view” EPUB files in nearly similar to the way that Internet Explorer “displays” a web site.
Just like a regular web site, the content pages of an EPUB file are written in XHTML code. And, like most web sites, an EPUB file also has a CSS style sheet along with and images folder full of .jpeg, .gif, or .png images. An EPUB creator should be skilled in writing HTML and CSS.
The EPUB format has the following major characteristics:
- EPUB is an open standard that is free.
- Text is an EPUB document can reflow and resize to adapt to the size of the e-Reader’s display and also conform to the font-size settings that the viewer has set on his or her e-Reader. Reflow has nearly the same meaning as the term “word wrap,” which occurs whenever text size or screen size are changed.
- Images are usually shown “in line” with the text. Images can also be positioned using basic CSS, such as “float left or right.” Images appearing in EPUB filess can be raster (.jpeg, .gif, or .png) or vector-based.
- CSS controls all styling in an EPUB document. Each EPUB document contains a cascading style sheet with all of the styles and formats that are used used in the document. An EPUB creator needs to be highly skilled at writing CSS.
- EPUB documents can containing “metadata.” Metadata is embedded, useful information about the EPUB file such as the author’s name, the eBook’s ISBN, and date of publication.
- EPUB documents should to be “validated” before they are uploaded online book stores. Validation is the process of verifying that the EPUB file conforms to the current EPUB standard set by the IDPF. Most online book stores will reject an unvalidated EPUB file.
- EPUB supports Digital Rights Management (DRM). DRM refers to technology that allows copyright holders, publishers, and hardware manufacturers to control access to digital content. DRM is one way to authors receive compensation for the promulgation of their material.