The speakers for this morning's discussion were asked to be practical, to limit themselves to giving an account of the essential uses of the EEG technique for clinical psychiatry, and to avoid, as far as possible, the theoretical and speculative aspects of the subject. No doubt the time has come for an attempt at re-appraisal. In the last 10 years EEG departments have been developed in most of the larger mental hospitals and nearly every psychiatric centre or group, be it mental hospital, out-patient department or child guidance clinic has access to an EEG department and refers patients for examination in increasing numbers.