Amazon. The book is Making Artisan Chocolates by Andrew Garrison Shotts. It wasn't expensive, which is a nice change in a textbook. I got it used on Amazon for about $14, including shipping.
It is very colorful, with lots of great color photography. It is written in a relatively light and breezy manner. It gives lots of good information, without having a dry technical manual feel.
I'm looking forward to reading more about making chocolates.