I'm still a couple weeks away from a finished version of the book (which will be sold via amazon), but I've "soft-launched" my site to allow for advance PDF purchasing. Not to mention the book draft is all online for free.

http://natureofcode.com/

Enjoy!  Please post issues and errors to:

https://github.com/shiffman/The-Nature-of-Code/issues (book)

https://github.com/shiffman/natureofcode.com/issues (site)

Dan