Woolie Reitherman, Les Clark, Ward Kimball, John Lounsbery, Milt Kahl, Marc Davis, Frank Thomas,
Eric Larson, and Ollie Johnston

The Nine Old Men were a group of supervising animators at the Disney studios.  They stared out
as the "Animation Board" in 1940 when the studio was trying to cut back costs.  The board was
formed to rethink the position of animator and find ways to make animators more productive.
Their major contribution was a major change in the production method where animation was
assigned on a scene basis rather than on a character basis.  That is, an animator animated all
the characters in a particular scene instead of animating one character then passing the scene
off to another animator to add the next character.  This rather simple change had a profound
effect on the quality of animation coming out of the studio.

Before this method was adopted, animators would specialize in a particular character.  For example,
Norm Ferguson was the Pluto guy.  You would complete the animation for one character then pass
the scene off which normally resulted in less-than-ideal timing and staging.
 
Handling all the characters in a scene required the animator to become more proficient but also
gave them much more freedom to experiment with how the characters were interacting with one
another.  This focus on character and interaction was a fundamental change in how animators
started to approach their scenes.