Bob Stein once defined the book as "a user generated media, where readers and sometimes authors congregate." In recent years, Kindle and Nook have stirred the pot, but that's definitely not the whole story. What, to you, is the future of the book?
Authors don't have readers, just like companies no longer have customers. In both cases, you have users. They use you to solve problems. The future of the book lies in its ability to solve the user's problem, and do so through an interface they love to use.