Written by two of the animators that were a part of the legendary era now known as the Golden Age of animation, Frank Thomas and Ollie Johnston, it's an interesting insight into not only the beginnings of the Disney company and how it operated in those early years before and during the Depression of the 1930's and beyond but also the people that are responsible for developing the medium and what we now know as the principles of animation. Most of the pages are illustrated with photos, sketches, animation cycles and full colour layouts which make it a joy to read through.
I found some good video examples of how, in just a few short years, the animation went from everything, limbs and objects alike, being completely malleable as if made from Play-Doh yet still very stiff and lifeless with scenes that just move from one 'gag' to the next without a sense of real storytelling, to actually having a basis in physics, adding that element of life that was missing while also telling an interesting story that would hold the viewers attention and make them feel involved and interested as to what was happening.
Plane Crazy - 1928
Through the Mirror - 1936