Tap the Magic Tree by Christie Matheson is an "interactive" book in the simplest way. You read it and do what it says, turning the page to see how the illustration has "reacted" to what you did. (Can the app be far behind?) This lovely trailer is simple, too. It clearly demonstrates what it will be like for a child to read the book. At two minutes it's a bit long, showing the whole book, but it's charming and done with excellent filming and audio. If you don't see the video on your device, click here.