"Imagine a world in which every single person on the planet is given free access to the sum of all human knowledge."
-- Jimmy Wales, Founder of Wikipedia
How to Think Like a Computer Scientist: Learning with Python
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