THE I'nOBLeM Or awareness during anaesthesia has existed since the introduction of the muscle relaxant technique. Any study of the problem must necessarily involve a study of the unconscious mind where such memories are recorded. It must also involve an understanding of some basic psychological mechanisms. The writer has attempted to correlate the published evidence, both clinical reports and research results, and evaluate this from his own experience in anaesthetics and clinical hypnotherapy. It is emphasized that this is a personal evaluation of a difficult subiect, in which "scientific proof", in its normally accepted sense, is virtually impossible. Historical The first account of "awareness" was a letter by Winterbottom, x published in 1950. A brisk correspondence followed, but there was a gap of nearly nine years before further reports appeared, as though anaesthetists were reluctant, or embarrassed, to make such events public. Then, in 1959, Cratt and Phillips ~ published a case and an editorial s appeared in which it was mentioned that "doubtless there have been others." Two more editorials appeared in the Lancet 4 and in Anesthesiology, ~ and reports of single or several cases were described by the following authors: