It was only in 1980 that the first recognisable magnetic resonance images of the human brain were published, by Moore and Holland from Nottingham University in England. There then followed a number of clinical trials of brain imaging, the most notable from the Hammersmith Hospital in London using a system designed by EMI, the original manufacturers of the first CT machines. A true revolution in medicine has ensued; in only a few years there are thousands of scanning units, and magnetic resonance imaging (MRI) has assumed a central importance in medical investigation. It is an extraordinary...