Sources of Free Books
The National Academies Press
Project Gutenberg - Public domain works (Shakespeare, etc)
Literature Project - Classics
UPENN Online Books Page
Atari Archives - Vintage computer books
Bruce Perens Open Source Series
 
Classics
Dante's Inferno
The Complete Works of Edgar Allan Poe
Beowulf
The Interpretation of Dreams by Sigmund Freud
Homer's Iliad &Odyssey
The Autobiography of Charles Darwin
Darwin's The Origin of Species
The Egyptian Book of the Dead
Hypnerotomachia Poliphili

Graphics Programming
OpenGL Programming Guide - the red book
OpenGL Reference Manual - the blue book
Pixar's RenderMan Reference (v. 3.2)
Computer Animation Primer (1984)
The Graphics Programming Black Book
V1: Xlib Programming Manual

Artificial Intelligence and Machine Learning
Machine Learning, Neural and Statistical Classification

Algorithms and Numerical Techniques
Numerical Recipes in C
Numerical Recipes in Fortran 77
Numerical Recipes in Fortran 90
Handbook of Applied Cryptography
Templates for the Solution of Linear Systems: Building Blocks for Iterative Methods
Problems on Algorithms
Lecture Notes on Algorithm Analysis and Complexity Theory
Algorithms and Complexity
Data Structures and Algorithms with Object-Oriented Design Patterns in Java
Data Structures and Algorithms with Object-Oriented Design Patterns in C++
Data Structures and Algorithms with Object-Oriented Design Patterns in C#
Data Structures and Algorithms with Object-Oriented Design Patterns in Python

Programming
Structure and Interpretation of Computer Programs [video lectures]
Watch What I Do: Programming By Demonstration
How To Think Like A Computer Scientist (C++)
How To Think Like A Computer Scientist (Java)
How To Think Like A Computer Scientist (Python)
Thinking in C++or here (translations: Spanish, Italian)
Thinking in Java or here (translations: Russian, French, Spanish, Portugese, Slovak)
Thinking in Patterns
Programming Ruby
Practical Artificial Intelligence Programming in Java
Loving Lisp, or the Savy Programmer's Secret Weapon
Principles of Object-Oriented Programming in Java
Various books on the Ada programming language
Advanced Linux Programming
Linux Kernel Module Programming Guide
The Linux Cookbook
Linux Device Drivers
Java AWT Reference from the O'Reilly Online Catalog
Java Native Interface: Programmer's Guide and Specification
Securing Java
The Unix-Haters Handbook
The Art of Unix Programming
The Linux Development Platform
Programming Linux Games
Common Lisp the Language, 2nd Edition
Open Source Development with CVS
Teach Yourself TCP/IP in 14 Days
Teach Yourself CORBA in 14 Days
Teach Yourself C++ in 21 Days
Optimizing C++
Firewalls Complete
Creating Applications with Mozilla
XForms Essentials
Embedded Software Development with eCos
ARM Assembly Language Programming
PC Assembly Language
The Art of Assembly Language Programming
Linkers and Loaders
Let's Build a Compiler
Compiler Construction with Flex and Bison
Parsing Techniques - A Practical Guide
Perl for the Web
Text Processing in Python
Logic, Programming and Prolog
Parallel Complexity Theory
How to Design Programs: An Introduction to Computing and Programming
JXTA

Computers - Commentary & Biography
Moths to the Flame: The Seductions of Computer Technology
HAL's Legacy - 2001's Computer as Dream and Reality
Noam Chomsky - A Life of Dissent
City of Bits - Space, Place, and the Infobahn
Fumbling the Future: How Xerox Invented, Then Ignored, the First Personal Computer
The Computer Revolution: An Economic Perspective
Free as in Freedom

Web & Networking
Web Client Programming with Perl
CGI Programming on the World Wide Web
Dive Into Accessibility: 30 days to a more accessible web site
Intrusion Detection with SNORT
Embedding Perl in HTML with Mason

Engineering
The Scientist and Engineer's Guide to Digital Signal Processing
Computer Aids for VLSI Design

Medical
Exeter Medical Library online textbooks
freemedicaljournals.com

Physics
A Heat Transfer Textbook
Lessons in Electric Circuits
Handbook of Space Astronomy and Astrophysics
Astronomy and Astrophysics
A New Science Strategy for Space Astronomy and Astrophysics
A Computational Fluid Dynamics textbook from MIT

Mathematics
Prime Obsession: Bernhard Riemann and the Greatest Unsolved Problem in Mathematics
Difference Equations to Differential Equations
Elementary Topology, A First Course. Textbook in Problems
Fundamentals of Model Theory
Interactive Real Analysis

Psychology
Animal Intelligence (1911)
The Ascent of Mind (1990)
The Inner Light Theory of Conciousness

Journals and Conferences With Free Articles Online

Misc
Journal of Artificial Intelligence Research
NEC Research Institute Scientific Literature Digital Library
ACM SIGCOMM 2003

Topology
Geometry and Topology
Proceedings of the Eighth Prague Topological Symposium
Proceedings of the Ninth Prague Topological Symposium
Galway Topology Colloquium
Topology Proceedings
Applied General Topology
Bulletin, Centro Internacional de Matematica


Video/Audio Lectures

Misc
ArsDigita University free video lectures and notes

Computer Science
Structure and Interpretation of Computer Programs (MIT)
Structure and Interpretation of Computer Programs (ADU)
Computer Graphics (P. Juell)
How Computers Work (ADU)
Object-Oriented Program Design and Software Engineering (ADU) - using Java
Algorithms (ADU)
Systems (ADU)
Software Engineering for Web Applications (ADU)
Theory of Computation (ADU)
Artificial Intelligence (ADU)
Database Management Systems (ADU)

Mathematics
Linear Algebra (Strang, MIT)
Mathematical Methods for Engineers (Strang, MIT)
Tr(-1)^F In Three and Four Dimensions (Edward Witten)
Applied Math Seminars (Duke)
Geometry/Topology Seminars (Duke)
General Mathematics Lectures (Duke)
Discrete Mathematics (ADU)
Applied Probability (ADU)

Physics
Introduction to Supersymmetry II (Dan Freed)
ITP Miniprogram on Geometry and Physics
String Theory Seminars (Duke)
KDI Semnars (Duke)
Special Lecture Series on F-Theory (Duke)
Lectures on Neutrino Physics
The Mechanical Universe...and Beyond - Good series regardless of your prior exposure to the subject
The Elegant Universe (NOVA) - A lay description of string theory and it's implications

Biology
Comparative Physiology (USC)
Dinosaurs (elementary level)
Canine Cataract Surgery
Anatomy on the Web (USC)

Chemistry
Chemistry (OK State)
Engineering Chemistry (NC State)
The World of Chemistry

Geology
Introduction To Sequence Stratigraphy (USC)