I knew about the book "How to Think Like a Computer Scientist: Learning with Python" for some time and read some parts of it online. This book is an introductiory text for programming beginners starting at the very first steps. The best thing about it is that it's published under the GNU Free Documentation License.
Some days ago I read about other Free books published by Network Theory Ltd. Together with the books from GNU Press we are heading into the right direction. Free Documentation for Free Software! In the future I'll think twice about buying anther book from one of the big publishers if it's not Free.