Common Lisp: A Gentle Introduction to Symbolic Computation
book by David S. Touretzky
Structure and Interpretation of Classical Mechanics
Introduction to Data Mining
Free Software for Busy People
Economics in One Lesson
many "theories?" like The Broken Window explained
Tales from the Programming Trenches
a load of programming books
Non-Programmers Tutorial For Python By Josh Cogliati
via OOPWeb.com
Producing Open Source Software
Free Online Books (mostly on smalltalk)
by Stéphane Ducasse
Free quick reference cards
The Zope Developers Guide
Gaboogle: its a blog of interesting ideas
Gaboogle » Blog Archive » When was the last time you’ve read a good book?
computerbooks.web.com
Free Computer Books, tutorials and Lecture Notes
Hacker Highschool
www.hackerhighschool.org
Free Programming and Computer Science Books