The occasional iconoclastic contribution excepted (Burns et al., 1992), recent times have been characterized by an historically remarkable consensus that the brain is the chief bodily organ of relevance in the study of behavioral disturbances exhibited by older people. The last 25 years have seen tremendous advances in our ability to examine the brain during life. The younger of the two editors was issued a card at the start of his clinical training on which he was required to document his attendance at a variety of radiological procedures. When he qualified 31 months later the box for the pneumoencephalogram was still unsigned, the Royal Melbourne Hospital's first computerized tomographic brain scanner having rendered such procedures redundant within a few days of his arrival. Today, with the ubiquitous availability of computed X-ray tomography (CT), easy access to magnetic resonance imaging, single photon emission tomography and brain electrical activity mapping together with the increasing research use of positron emission tomography, that first scanner seems like a 78r.p.m. acoustic phonogram in comparison to a state of the art CD player.

Just as improvements in musical recording technology have not always been accompanied by a corresponding rise in the quality of performances to preserve for posterity, successive refinements of imaging technology have not necessarily marched in step with an increase in the sophistication of clinicians' use of such machinery. Most of us have long since ceased to expect a definitive diagnosis of dementia to be made from the result of a CT scan alone, the overlap between the normal aging brain and that of the patient with Alzheimer's disease being too great to allow easy discrimination between two isolated examples of each.