Intellectual property
Since the book and the hypertext are meant to complement one another, in order to experiment with different ways of presenting the argument, about twenty-eight percent of the hypertext contains material that overlaps about thirty-five percent of the book.
I feared that this might cause publishers to worry that people would take the free material on the web and forego buying the book. To my surprise, this did not seem a major concern to the publishers, though none of them had to face the issue head on since they were not committed to the project. I am still waiting for word from the latest book publisher.