Well, I can suggest a few books I've read. Links are to Amazon. They all have a nice preview, so you can gauge how effective they might be for you.
How to Use an Airbrush (2001) - when I started this was the only airbrush book for modeling, thought it's outdated. It focuses on using an airbrush primarily.
How to Use an Airbrush 2nd Edition (2008) - Like the last one, this is more about using an airbrush on specific models, not really blanket techniques or what to look for. And several of the models appear in both books.
Airbrushing and Finishing Techniques (2008) - This is probably your best bet (and most expensive). They talk about several airbrush types, accessories, techniques, etc., and it's fairly up to date. The downside is that it focuses mostly on aircraft. And there are a lot of techniques/theories (like color modulation) that seem a little overwhelming (especially being crammed in the beginning of the book).
Although, going back to your hammer analogy, finding the best is probably going to require mostly online searches. Everyone seems to have their favorite airbrush that they swear by. There are even people who love the Testor's Aztek series that I (and a lot of acrylic users) can't stand.
Best of luck though in finding a good resource. I'm beginning to think finding a good resource is harder than finding a good AB.
Action Fleet Unlimited: Star Wars models, customs, toys, techniques, and scale lists (with a few non-SW models thrown in)
Cheers