I am a Bulgarian award-winning author of first of its kind gamebooks for little children. Now my first book - GameTale: The Big Adventure of the Little Gremlin is available as a free download (PDF, iPad 2+, Kindle Fire) in English: http://gametale.eu/the-books_1.html
Here is a short trailer for the book:
I hope you check it out with you kid(s) and give me some feedback. I will highly appreciate that!