For ten years before the creation of Mickey Mouse, Walt Disney struggled with, failed at, and eventually mastered the art and business of animation. Most biographies of his career begin in 1928, when Steamboat Willie was released. That first Disney Studio cartoon with synchronized sound made its main character--Mickey Mouse--an icon for generations.

But Steamboat Willie was neither Disney's first cartoon nor Mickey Mouse's first appearance. Prior to this groundbreaking achievement, Walt Disney worked in a variety of venues and studios, refining what would become known as...