"since anim8or is free so should the book".
French is a free language, but there are thousands of books out there that teach you how to read it and how to speak it.
HTML is a free programming language, requires nothing more than a computer, and there are extensive tutorials online, yet, every year hundreds of new books on the subject come out.
Blender is also a free program, yet has books.
If you want to write a book, and teach people how to use anim8or, and someone wants to buy it, what's the problem?
As a matter of fact, I first heard about anim8or in a book about game programming, and it had an extensive explination of how to use anim8or to create your objects.
If someone goes through the trouble of writing a book (A good book mind you), on using anim8or, why should they not get paid for their work?
Sage