An investigation is described into the problems of recall and dreaming under light anaesthesia with nitrous oxide, muscle relaxation being provided by tubocurarine, and the anaesthetic technique being, as far as possible, standardized. Tape-recorded music of two types was used to test the patient's ability to hear and, in addition, the nature and quality of dreams was investigated. There was no evidence that patients were able to hear the tape-recordings and there was no evidence of “awareness” during the operative procedure. Dreaming occurred in 44 per cent of the patients and details of the dreams were recalled in some two-thirds of these. Hypocapnia did not protect against dreaming. Patients who showed marked movement during the operative procedure were more liable to dream than those who did not; the significance of this movement is discussed. In this (unpremedicated) group of patients nearly half described waiting for surgery as the most unpleasant feature of their surgical experience, and postoperative pain was the major complaint in a further 20 per cent. The third commonest of the major complaints was related to requests to lift the head, etc., when unable to do so in the time immediately after operation, and this finding would seem to have some minor practical significance. Unpleasant dreams were the fourth commonest major complaint.
