I'm not sure, but this might be good news for people that have been wanting to get this book, but didn't have a Mac or iPad. Apparently, iPhone seems like an option, but I'm not sure if/how it actually works.
I tested it out today. The Interactive Stencyl Textbook is better on the desktop / iPad, but it is usable on iPhone. The free sample is a great way to test. That way, you can see if the results are acceptable to you.