Hundreds of millions of tablets and e-readers have been sold, but today we’re still inclined to think of a book as words on a page. Amazon’s success with Kindle has hinged on recognizing how much more they can be. So where does the company go from here? In a series of rare, on-the-record interviews for Kindle’s 7th anniversary, Amazon executives sketched out their evolving vision for the future of reading. It’s wild – and it’s coming into focus faster than you might have guessed.