I’m impressed with the “hacks” books (Google Hacks is another one) — very little theory, all practical examples. A lot of developers (myself included), learn best by reverse engineering. Give me something that works, and I’ll tear it apart, put it back together, and be smarter for the experience.
Hats off as well to Amazon and Google for being ahead of the curve enough to allow this level of API access to their services. I’ve used the Google API, and it’s fantastic. Chris has used the Amazon API (on this site, no less), and done some great things with it.