I'm a bit of a book nerd and like to collect books on animation techniques, artistic processes and artists, studios and animators, and any other interesting artistic processes like games, colour theory and drawing.
Below are some of my recommendations.
This is a classic book on traditional animation techniques and exercises, written by the late great Richard Williams (Who Framed Roger Rabbit). A recommended book for starting out in animation.
Another classic book on the history of animation, written by Frank Thomas and Ollie Johnston who worked for Disney during the golden years. It speaks a bit about the principles of animation, but it's mostly stories from working in the studio.
This is a great book to learn effects animation, written by Joseph Gilland. Foreword by Michel Gagne who has worked on nearly every major 2D animated film in the late 90s early 00s.
A great book which talks about colours, the history of certain colours and how they all work together.
"Game Anim: Video Game Animation Explained" is a book by video game developer Jonathan Cooper about how video game animation works.