Flexpaper is an open source document viewer--and it is beautiful. The Flexpaper API lets you incorporate your publications into other applications. Flexpaper works on virtually any device and is, no surprise here, flexible. It can display in HTML, HTML5, Adobe Flash or any combination of these.
Before 1500, monks spent their lives copying the Bible by hand. That method was replaced by printing presses for the next 500 years. Today, ebooks are set to end the practice of pulping trees and smearing them with ink. In all this change the direction of information access has been constant for half a millennium: faster and faster, easier and easier. The next revolution for publishers is APIs for books.