The recent history of anesthesia and implicit memory begins with a young South African trainee anesthetist called Bernie Levinson who was working in London in the late 1950s. He was shocked at the pejorative remarks made by surgical staﬀ about the patients lying apparently unconscious on the operating theater table. Levinson was convinced that these remarks must be processed in the anesthetized brain at some level and that they must have had a detrimental eﬀect. He then set about attempting to prove this through an experiment which, these days, would not get past a hospital ethics committee. Using ten dental surgery patients, he role-played a ﬁctitious anesthetic crisis. After administering the induction anesthetic and allowing the surgeon to begin, he shouted “Stop the operation, I don’t like the patient’s color. His/her lips are turning too blue. I’m going to give a little oxygen.” He then waited one minute and then said to the surgeon “OK, everything is ﬁne now.” One month later he interviewed the patients and hypnotized them, and gave instructions designed to “regress” them back to the time of the operation.