What’s a Book App and Should You Create One?

"A book app is an interactive eBook book that works on a mobile device like a tablet computer (the iPad or Samsung Galaxy), a smart phone (like the iPhone) or a device like the iPod Touch.

Think of it as an “eBook on steroids” because book apps go beyond the illustrated eBook to include features like narration, sound effects, interactive storytelling, animation and more."

http://www.sellingbooks.com/whats-a-book-app-and-should-you-create-one/