The human nervous system-that most complex organization of energy and matter-has yielded a few glimmers of understanding of its operational me- chanics during the last two decades. These have mostly been at the biochemical level of structure and function. Throughout history, as one of the mysteries of nature begins to yield some insights into its function, it has been beneficial to look at it from different points of view. We have developed a volume on movement disorders that is primarily directed toward the biochemical understanding of these disorders and their treatment. Each disorder is...