Over the past decade, we have witnessed a dramatic acceleration in the application of magnetic resonance techniques within the medical sciences. Following the original experimental demonstration of the NMR phenomenon by Bloch and Purcell in 1946, emphasis was directed toward the study of physical materials: however, in the 1950's and 1960's, research was reported on the use of NMR to investigate the properties of biological materials including cell systems, excised muscle tissue and certain in vivo models. This book fully discusses this important topic.