This book reinforces the view that the cerebellum functions as an adaptive control system, automatically adjusting its output as needed for such eventualities as temporary or lasting muscle weakness. It is the first text to synthesize the substantial body of literature on the subject, combining the neuroscience of the cerebellum with the science of control theory common to electrical and computer engineers. An appendix demonstrates evidence to support the adaptive control model from a detailed comparison of the cerebellum with an adaptive signal processor of the author's design and construction. In addition, the author's clinical perspective offers a broader view of cerebellar function beyond basic neuroscience.