When I first started writing Paperless, the iBooks store did not exist. There were no snazzy tools for me to incorporate rich-media with text and I was facing up to the fact that I was going to have to Frankenstein ePub and PDF to get what a wanted, a book that not only told you how but also showed you how. I spent weeks researching and testing and still didn't have it nailed down. Then Apple announced iBooks Author and the iBooks store and I immediately abandoned all prior efforts and jumped to the new platform. iBooks Author gives me exactly what I need to publish the books I want to make.
I didn't stress this enough when I launched my first book on the iBooks Store: iBooks Author has its quirks, but the fact that a guy like me can put together an interactive book and sell it in over 50 countries with no additional fees is pretty amazing.