Preston Blair is the number one source for an aspiring artist to learn the principles and design of animation. However I could recommend many other books that have their own uniqueness in teaching artists that don't have exactly the same principals or style as Blair. Like (The Aniamtors Survival Kit) by Richard Williams but that is a another topic.
Blair is a versatile artist from his days working at the conservative parlor of Disneys to his more vivacious years at MGM working under the wing of creative genius Tex Avery. While I commend both studios places like MGM especially under Avery's unit gave artists more room to express creativity to their hearts content. While Disney was a bit more restrictive and had his own personal vision on how things should be done.
This was not from the book Cartoon Animation I still studied Blair through watching Red Hot Riding Hood and its sequels. Watching the dance steps and poses of Red really gives you a hold on the character and their anatomy.
Proudly I didn't trace any of it all free hand and all from studying frame by frame something I couldn't have said ten years ago.