Writer Christopher Fowler bangs up against the two Ds that limit the widest acceptance of eBooks, DRM and Design, in this post: eReading: The Love Affair Wanes
DRM:
But I hate it for DRM – the outrageous rip-off of digital rights management that prevents me from reading the e-book I have just paid for. Purchasing ‘The Psychopath Test’ by Jon Ronson on Kindle For Mac, I found I couldn’t translate it to my Sony because it was protected, which is like someone selling me a book that I can read in my home but not on a bus.
Design:
… Kindle, which appears to have been designed by monkeys who like steampunk.
Yes, Chris did what many of you do — and I know you do, so STFU — buy a Kindle book and then strip it and convert it to ePub.
In this case, it seems the DRM — or something — has defeated his plans for this book. (I’d be surprised to learn it’s in TPZ file format. Does anyone know?)
Mike Cane’s xBlog 
The file for “The Psychopath Test” is .azw. Yes, I had to buy it to find that piece of info but it looked interesting. ^_^
Say no more.