The volume summarizes the most recent knowledge in the field of motor system (upper and lower motor neuron) physiology and pathophysiology as related to diseases of this system. It covers the various aspects of motor system disorders from the motor cortex to the spinal anterior horn cell. Emphasis is placed on clinical disorders as they affect the human motor system and includes critical discussion of advances in techniques for diagnosing and understanding the pathophysiology of disorders affecting the motor system, describing approaches to characterization of disease type, location, severity and prognosis. There is discussion of the specificity and sensitivity of methodological techniques used in diagnosis, with comparison among the various methods.