Patients with the amnesic syndrome have an unclouded sensorium and appear alert, able to concentrate and are cooperative. Perceptual and intellectual skills are preserved. Amnesic patients do not score differently from normals on tasks that require the immediate reproduction of a sequence of stimuli not exceeding the capacity of the short-term (working) memory store (memory span). Amnesia does not affect equally memories acquired after and before the onset of disease (anterograde and retrograde amnesia, respectively). The study of amnesia has been of paramount importance to the identification of the cerebral structures that mediate memory. The amnesic syndrome, although rare in clinical practice, remains extremely important theoretically for understanding the organisation and neural basis of memory. There is still debate as to whether the amnesic syndrome represents a unitary entity, but there is clear variability in the extent of remote memory loss depending upon the site of pathology.