This book was exactly what I was looking for. It had detailed instructions for how to perform nearly every task in Character Studio (now just called the biped system in 3DS MAX). It's not going to have anything conceptual in it.
If you want a comprehensive animation guide, you need to get the animation bible (The Animator's Survival Kit: A Manual of Methods, Principles, and Formulas for Classical, Computer, Games, Stop Motion, and Internet Animators) in addition to this. Make sure you know everything about squash and stretch, anticipation, etc. Come to think of it, start with the book The Illusion of Life: Disney Animation (you can find a lot of this info online, because it's so old, but it's good to have it when you're not on the interwebs as well).
Actually, you can start with whatever excites you most, but you won't get anywhere interesting without the foundational concepts in these two other books. They apply to even the realistic kinds of animation you see in action movies. In fact if you're going to Mo-Cap everything you ever do, you should still know them.