"When did the copyright holders become the Corporations? Who owns the Intellectual Property? Who controls our Arts and Sciences? They are slowly eroding our rights. The authors, scientists, researchers, students and you are very much at risk."
by Peter Wentworth, Jeffrey Elkner, Allen Downey, and Chris Meyers
An introductory computer science text book using Python.
by Tony R. Kuphaldt
A free series of textbooks on the subjects of electricity and electronics