The rapid pace of advance in the basic and clinical sciences has led to striking changes in the practice of medicine. This is particularly evident in clinical neurology. Twenty years ago neurology was justly criticised for its preoccupation with diagnosis and classification, and for the relative paucity of treatments then available. All this has now changed, and neurology has become a treatment-oriented specialty. This change has been brought about partly as a result of the introduction of new and accurate methods of diagnosis, especially immunological, electrophysiological and imaging techniques, and partly as a result of new forms of treatment. Examples of these new treatments include the control of cerebral edema, new antibiotics for infections of the nervous system, drug level measurements for the evaluation of the adequacy of treatment of epilepsy and advances in neurosurgical technique. In addition, many patients presenting with neurological disorders are found to be suffering not from primary diseases of the nervous system but rather from neurological compli cations of systemic disease. Vascular disease, cancer and infections are common examples. The degenerative disorders have recently become a focus of attention as their importance in the aging societies of the developed Western countries has been realised, and this raises the hope of improved management and treatment of these disorders.