The iBooks app is a great new way to read and buy books for the iPad. Download the free app from the App Store and buy everything from classics to best sellers from the built-in iBookstore which is part of iTunes. Once you’ve bought a book, it’s displayed on your Bookshelf. Just tap it to start reading.
There isn't much information available about this application. What we know is:
- it supports ePub format.
- it will use Apple's FairPlay DRM scheme to protect some eBooks purchased via iTunes. This will limit the use of these eBooks to Apple devices.
- it will be able to import ePUB books from other sources via iTunes desktop
- touching and holding any word lets users look it up in the built-in dictionary, on Wikipedia, or search for it in the book or on the Web.
- TTS via iPad's VoiceOver screen-reading technology
 iBooks 2
Version 2 has added specific support for text books and moves closer to ePub 3 features.
- Multi-Touch textbooks designed for iPad
- iBooks textbooks include interactive features, diagrams, photos, and videos
- Tap to dive into images with interactive captions, rotate 3D objects, swipe through image galleries, watch videos in full screen, and more
- Use a finger as a highlighter when swiping over text in a textbook
- Take advantage of Study Cards to help you memorize important highlights, notes, and glossary terms
- Tap glossary terms to see definitions of key topics and concepts without leaving the page
While iBooks reads ePUB files it does have extensions that are not necessarily ePUB compliant.
- Expandable photo blocks in iBooks - zoom images.
- Version 1.2 and later supports a new Fixed layout ePub which is unique to this reader.
- Padiliciouse multi-column layout - article. Other articles are available from the site.
- If the cover doesn't show up, you can open it in Sigil, browse to the "Images" folder, right click the image, select "Add Semantics" and choose "Cover".
- Embedded fonts will not be used by iBooks unless a special file is included in the ePub with special content. The file is: META-INF/com.apple.ibooks.display-options.xml and must contain:
<?xml version="1.0" encoding="UTF-8"?> <display_options> <platform name="*"> <option name="specified-fonts">true</option> </platform> </display_options>
 Known Issues
"In some cases, you may find book pages are missing or repeated at the end of a chapter, or text in the chapter appears truncated in an ePub digital book in iBooks." Here's the full article from Apple support: iBooks: Pages missing or repeated in ePub. Making code as clean and light as possible by removing empty spans and extraneous code from originating software or document minimized the issue.