Science and Technology of Rare Earth Materials reviews the important aspects of the science and technology of rare earth materials, covering the entire spectrum from occurrence to extraction and purification, phase relationships, electronic structure, and applications. This book is organized into five sections encompassing 19 chapters. The occurrence, extraction, and production of rare earths are discussed in the first section, followed by purification methods employed for rare earths, together with the role of impurities on their behavior. The phase relations among the rare earth alloys, including a particular reference to the technologically important rare earth-cobalt alloys, and phase relations among the rare earth oxides are considered in the second section. The succeeding two sections focus on studies of the electronic structure of rare earth materials, with emphasis on the use of nuclear magnetic resonance and Mössbauer spectroscopy. Theoretical conceptions are set forth as well as the effect of crystal fields and valence fluctuations on the properties of rare earth systems. The final section describes some of the extensive current uses of rare earth materials such as in the steel industry and in permanent magnets, as well as emerging applications in catalysis, hydrogen storage, ferroelectrics, and fast ion conductors. This book is a valuable resource for researchers and students interested in rare earths.