If you have any Lisp experience at all, you almost certainly know about Peter Norvig’s classic Paradigms of Artificial Intelligence Programming (PAIP). It’s an excellent introduction to Lisp and, of course, Artificial Intelligence. Via Rainer Joswig we learn that PAIP has been open sourced.
The GitHub repository contains the book in PDF, Text, epub, and Markdown source. The example lisp code is also included. If you have any interest at all in Lisp—and in particular in Common Lisp—you should definitely take a look at this book. The markdown files are by chapter so it’s easy to sample them directly in GitHub, which will render the Markdown in a reasonable way. If you find that interesting, you can download the PDF or epub files for local reading.