Even the earliest applications of nuclear magnetic resonance (NMR) spectroscopy and tomography to medical inquiries, using experimental apparatus that was primitive by today's standards, demonstrated the extraordinary potential of the NMR method. The subsequent rapid advances in this area were due largely to the ef- forts of commercial manufacturers, who, by improving magnet and computer designs, were able to produce and market instruments having a remarkable image quality. Experimental data from the ftrst systematic studies on the medical uses of NMR leave little doubt that NMR will gain a...