This is the book I've been looking for the last five years without realizing it. It presents a theoretical approach that unifies all of the bits and pieces of the psychology I know. Influence tied a nice little bow around everything -- pretty fantastic.
What I got out of this book was not so much how to influence people, but more how to influence myself, and the lines along which I should expect to be influenced. Every two pages I found myself staring out into space while I tried to connect all the dots in my mind. I'm not sure if others would get as much out of this book as I have, but I'd recommend it anyway.