A friend send me a DRM free version of Make's 3D Printing Book. Follow the link to check it out if you are interested.
https://docs.google.com/file/d/0BxCHqlUoqCJgX0hEQWUyT0tIbGs/edit?usp=sharing&pli=1
If it is useful to you, obviously, go buy a copy to support the author...