Drugs affecting the nerves and the brain are among the most commonly used in contemporary medicine. This book examines the mechanism by which such substances cause their therapeutic effects or undesirable side-effects, in relation to underlying physiological and pathological processes. This new edition has been extensively revised and reorganised; the section on the autonomic system has been greatly expanded. Other changes reflect the significant advances in our understanding of drug action in the peripheral and central nervous systems which have arisen through the application of new electrophysiological and computer techniques. The volume summarises the explosion of information concerning endogenous opioids, other peptides, the benzodiazepines and their receptors. Later chapters deal with the activity and role of drugs in a number of disorders including epilepsy, schizophrenia and depression. This textbook is suitable for undergraduates in pre-clinical medical sciences, pharmaceutical and natural sciences; and for post-graduates and trainees in neuroscience, psychiatry and anaesthesia.