Over the past 10-20 years there has been an explosion of work on the disturbance of motor control that is manifested as spasticity. This work has been based on new insights from animal experiments into the basis of normal motor control and the development of experimental techniques that could be used in patients with neurological disturbances. For this reason, on the initiative of Alfred Thilmann, the editors of this volume organized a workshop on spasticity, held in Essen, Germany, in November, 1992. The intention of the meeting was to bring together leading scientists in an atmosphere that would generate discussion and hopefully consensus and ideas for future work. The attendance was restricted and deliberately selective, with a mix of basic scientists, clinical scientists and practicing clinicians. The product of their presentations and deliberations is this volume. The book is organized in the same sequence as the workshop, so that the discussion sessions could be summarized by the appropriate chairman.