[AX7221]

I'm no expert, but here's what i recommend you look for in any book:

Don't get a book that tells you what to memorize, like a math teacher would never tell you to memorize steps. The reason is that you can't build off of something that's memorized. If you learn something and understand why it is then you can build off it. I've talked to someone who said that music is all arbitrary b/c music origionated from nobles who decided what they liked and it was played... The point is before i go off topic is everything in a book on music theory is like that for a reason and its basically essential to know why for the long run. So dont get a book that says this is the way it is and that's that, get a book that teaches you why it is, then you can make connections and so forth. I just got the plane talk book that is excellent for that reason, but its a pricy book so it depends on how much you already know...

It's also important to have reference books in addition.