On-Line Books

C++

How to Think like a Computer Scientist in C++

Java

How to Think like a Computer Scientist in Java

Python

How to Think like a Computer Scientist in Python

Learning to Program in Python

Linux

Writing Linux Device Drivers (PDF)

Network Administration Guide

Other Books

The Thinking in C++/Java/Python series of books by Bruce Eckel is available for free download. Unfortunately, I could not find a site that made them available in online form. (And it is too large for me to make it available online here.)