The Animators Survival Kit by Richard Williams has become my bible since I first picked it up a couple of years back. Where Illusion of Life teaches you to think like an animator and consider what you are doing, the Survival Kit just says, do it and learn from your mistakes. An approach that I genuinely like and that has both advantages and disadvantages.
What I really like about the survival kit is that it is right in your face. It says..."look this is how you do stuff, so just memorise it and get on it with it". That's what it would be like in the studio, you would be shown something, told to learn it and then repeat it. This is a great introductory book because it gets you away from static shapes and teaches you to work like an animator, considering mass, shape and balance in all of your drawings.
This book is full of techniques and little things to remember, tips and tricks that you would only learn from years of experience given to you right from the start. How lucky are we to be able to gain 40 years of experience in less than 500 pages. Richard Williams further emphasises certain other techniques and things to learn that you might not consider, such as life drawings. I have never been a fan of life drawing, but I know that if I am to become a better animator I need to follow his advice and study the way things move around me. I took that in from the very start and I often just sit and watch people walk by. My friend has the funniest walk I have ever seen and I have tried to draw it several times without avail. I think when I do get it right I will know that I moved up a step on the ladder.
The principles and techniques are all here from a man who has decades of experience and two Oscars to boot. The fact that he has put it all in a book for the rest of us is nothing short of the nicest thing in the entire world. Now if I can just master it :P