More from Allen Downey (full version – recommended – here).
A free license is not just a different way to distribute the same product; a book with a free license is a fundamentally different product.
… one advantage of free books is turnaround time. Another is low activation energy; I didn’t have time to write a conventional textbook. I probably never will. But I had time to write a free textbook (barely), and that was the beginning of a process that turned out to be surprisingly cumulative.
A free book is the root of a tree of potential adaptations, translations, and entirely new books that branch out from the original. Free books transform readers into proof-readers, editors, anthologists, correspondents, contributors, collaborators, writers and authors.
If you are thinking about writing a book, start soon, release early and often, give up control but do a little policing, keep a contributor list, and make it free.Allen B. Downey – Free Books, Why Not?