I've never been totally sold on the whole idea that an animator is just an actor. While they can be similar, an animator's challenges in creating performance are different from a stage or film actor. Getting an emotional performance from within yourself expressing it with your physical body takes different tasks than expressing it outside yourself on paper, or even worse, through a complex computer interface onto a 3D model.
Action! Acting Lessons for the Animator is basically a survey of various acting techniques and doesn't have any serious animation training.
The actual "animation exercises" is this book are actually rather worthless. They simply involve importing a still or video clip of the acting students and copying their poses with the 3D model; basically just Rotoscoping. There's more to being an animator than just doing what a stage actor does and simply copying it into an animated character.
The first few chapters are basic history and explanation of method acting. It's mostly just traditional theatre warm up, stretching and acting exercises that might not appeal to an animator.
One of the most intriguing ideas in Ed Hooks'Acting for Animators, Revised Edition: A Complete Guide to Performance Animation is that of power centers and how it affects movement. It's not mentioned much in this book and the video examples were shot with the camera turned sideways so the actors walk from the top of the screen to the bottom, making them totally worthless.
Chapter 4 covers Comedia del'Arte with its cast of stock characters who each have a set list of expressions, poses and gestures. It's interesting to see, but not as useful compared to other techniques.
Chapter 5 is on Bioenergetics, the idea that certain personalities have different tensions that affect their movement. It's a little hard to grasp, at least the way they're demonstrating it. The video examples on the disc show people walking like Frankenstein and other over-exaggerations, so it'd take a lot more study to use bioenergetics well in animation.
Chapter 6 is on the acting techniques of Michael Chekhov, which involves coming up with actual gestures to define a character. It's fairly well done, but could've gone further.
What might've helped would be depicting and pushing these poses and actions in drawn gestures before translating them onto the 3D character. But that also seems against the scope of a computer-specific publisher like Sybex.
Chapter 7 is on essences; incorporating qualities of animals, objects, etc... into a character. This is incredibly well-suited for animation and is already done all the time, especially with non-human characters. This chapter just expands on it some.
Chapter 8 is a pretty good summary of Laban Effort Analysis, which defines measurable qualities of motion. This is a good thing to pay attention to, if just so you can consciously make characters move differently from one another.
Chapter 9 is on Alba emoting technique, which uses posture and breathing to help summon emotions in an actor. Since it's basically about triggering emotional responses within yourself, I don't think it's as useful in animation as the authors think it is. This looks to be a very powerful technique in a real, living actor, but since an animated character can't be biologically affected be its breathing, all you're left with is basic pose or facial expression to depict an emotion. Plus once you move past the 6 basic emotions the technique focuses on, it's all a lot of guesswork anyway.
The last two chapters are on voice acting and lip sync/facial acting. It has some interesting points, but still sticks to simply copying the actor reference.
All in all, this book does have useful ideas worth thinking about, but you're going to have to do a lot of work to incorporate it into actual animation work. So I suggest buying it, just not for full price.