I just spotted this on comp.ai.genetic. The authors of a new book called A Field Guide to Genetic Programming have made it available for download in PDF form free of charge. Weighing in at around 200 pages, it looks like a reasonably concise introduction to the topic (unlike some of the huge and hideously expensive GP books you can buy on Amazon).
This is good timing for me because I’ve recently started hacking together a GP example application to include in the next release of the Watchmaker Framework for Evolutionary Computation. So I can catch up on a bit of background reading to make sure I’m doing things sensibly. Watchmaker is a general purpose evolution framework, intended to address the full range of evolutionary algorithms. I’ve been claiming for a while that you can use it for genetic programming, so I thought it was about time I demonstrated this. I’m not aware of anybody having used Watchmaker for GP so far. I’d love to hear from anybody who has done so.
Genetic programming is also covered in an accessible way in Toby Segaran’s excellent book, Programming Collective Intelligence, which includes GP examples in Python.