How to roleplay every NPC (almost!)

I recently came across the idea of a psychological gesture from Justin Alexander of the Alexandrian. This is a technique created by Michael Chekhov where actors use a physical action to capture and express their character's main emotional or psychological state. I've been trying it out a bit, and it's fun and really helps me get in character quickly. 

So You Want to Be a Game Master: Review

If you're serious about DMing, you will know who Justin Alexander is. So what is his new book all about, and what did I make of it?