On this day in 1981, ‘The Illusion of Life: Disney Animation,’ a book by “Nine Old Men” animators Frank Thomas and Ollie A. Johnston was released. It is widely considered to be one of the best and most complete books ever published on the subject of character animation. It describes the painstaking trial-and-error that animation requires. The book includes some early versions of Disney favorite characters, such as Mickey Mouse, Donald Duck, and Snow White.