Today is the big update for Apple not only did iTunes receive a major update, iBooks also saw a major update earlier today. The update included a number of features missing both from iBooks and the iPad Kindle app, such as:
• Double-tap an image within a book to view it in greater detail.
• Experience books that include audio and video.
• Enjoy substantial performance improvements when reading PDFs.
• Look-up definitions to English words inside books without a specified language.
• Addresses an issue that may have caused some book downloads to not complete.
• Includes many stability and performance improvements.
You can download the update through iTunes or the App Store on your device, or grab iBooks from the App Store for free if you don’t already have it.