"As we enjoy great Advantages from the Inventions of others, we should be glad of an Opportunity to serve others by any Invention of ours, and this we should do freely and generously."
-- Benjamin Franklin
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