We report the case of JC, a young man who became amnesic 10 years ago following a ruptured aneurysm on the left posterior cerebral artery when he was 20 years old. JC has learned to compensate for many of his problems by using a sophisticated system of external memory aids. Because relatively little is known about the development of compensatory behaviour in people with amnesia, we describe the natural history of the development of JC's memory compensation system.