Research on amnesia basically involves identifying the patterns of memory and cognitive breakdown that result from brain lesions with particular locations. It has long been understood that this requires the development and use of hypothesis-driven memory and cognitive tests as well as the use of standardised tests and test batteries. But until the 1970s and the emergence of computerised tomography (CT), it was not feasible to identify the location of the lesions that caused the memory breakdown with any accuracy in life. Only if it was possible to perform a post-mortem analysis could the location of the underlying structural lesions be identified, and this could be decades after a patient’s neuropsychological profile had been examined. Relatively few postmortem anatomical analyses have been carried out, but those that were performed did indicate that particular aetiologies of organic amnesia, such as herpes simplex encephalitis and alcoholic Korsakoff syndrome, were associated with reasonably specific areas of brain damage, even though this brain damage was almost invariably not confined to single brain structures. Research on amnesia, therefore, tended to involve the comparison of patients or the study of patients in different aetiological groups, on the assumption that patients within an aetiological group would have reasonably homogeneous kinds of brain damage, and that the location of this brain damage would vary much more across, rather than within, different aetiological groups.