With the increased interest in superconductivity applications through­ out the world and the necessity of obtaining a firmer understanding of the basic concepts of superconductivity, the editors of the In­ ternational Cryogenics Monograph series are extremely grateful for the opportunity to add Superconducting Materials to this series. This comprehensive review and summary of superconducting ma­ terials was originally prepared by the Russian authors in 1969 and has been specifically updated for this series. It is the most thorough review of the literature on this subject that has been made to date. Since advances in the development and use of new superconducting materials are largely associated with the general state and level in the development of the physical theory of superconductivity, the physical chemistry of metals, metallography, metal physics, tech­ nical physics, and manufacturing techniques, it is hoped that this monograph will provide the stimulus for further advances in all aspects of this exciting field. The editors express their appreciation to the authors, the translators, and Plenum Publishing Corporation for their assistance and continued interest in making this worthy addition to the series possible.