Ahhh...Don't Shoot the Dog and Turid Rugaas are also great but I didn't see them as "core" books to start.....but absolutely worth the read. As a great complement to Turid's "Calming Signals", you should also check out Patricia McConnell's DVD on her seminar regarding reading animal behavior - EXCELLENT and so necessary for the mass public.
On another note, I agree that Patricia's Other End of the Leash is a great explanatory book of the difference between human and canine and explaining their behavior. If you want her "how to" then check out her how to short books such as "Puppy Primer", "Feisty Feido", "Pack Management" et al. All available depending on the behavior need or canine phase of life.