More than any other performing art, dance is dependent upon the memories of its practitioners to keep its history alive. There may be an extensive vocabulary used to define the basic positions and steps of classical ballet, but there is no perfect way to write down a dance in order that future generations might dance it again. “Even today, despite the advent of video, a choreographer without disciples is in constant danger of having his work fade away after his death. Video can capture the external form and movement, and notation the positions, but the philosophy and technique of the great choreographers is impossible to get down.”