In the seven years since the first edition of this book was published there have been many important developments in knowledge of neuromuscular diseases. These are reflected in this new edition. We have taken the opportunity to add much new clinical and scientific material to the book, particularly in relation to metabolic myopathies and neuropathies, and to include more information on genetic aspects of neuromuscular diseases, quantitative electromyo graphic techniques, plexus and root lesions and cardiomyopathies. The aim of the book remains unchanged, but we have rearranged some of the material so that there are several new chapters. The illustrations have also been extensively revised and there are many new references. We hope that it will continue to provide a convenient source of practical and theoretical information that will not only be useful in managing patients with neuromuscular diseases, but will stimulate research. London, May 1987 Michael Swash Martin S. Schwartz Preface to the First Edition Neuromuscular diseases are common in clinical practice. Patients with these disorders may be referred to neurologists, rheumatologists, orthopaedic surgeons, paediatricians or to general physicians, and their investigation, utilising electromyography (EM G) and muscle biopsy, often requires the help of the clinical neurophysiologist and of the pathologist.