http://withouthotair.com/about.html http://withouthotair.com/about.html - "This is a free book in a second sense: you are free to use all the material in this b

http://withouthotair.com/about.html http://withouthotair.com/about.html - "This is a free book in a second sense: you are free to use all the material in this book, except for the cartoons and the photos with a named photographer, under the Creative Commons Attribution-Non-Commercial-Share-Alike 2.0 UK: England & Wales Licence. (The cartoons and photos are excepted because the authors have generally given me permission only to include their work, not to share it under a Creative Commons license.) You are especially welcome to use my materials for educational purposes. This website includes links to separate high-quality files for each of the figures in the book. A note to pirates, this license does not allow you or anyone to print and sell the book on amazon marketplace!"