X-ray absorption fine structure (XAFS) is a powerful technique in characterization of structures and electronic states of materials in many research fields including, e.g., catalysts, semiconductors, optical ingredients, magnetic materials, and surfaces. This characterization technique could be applied in a static or a dynamic state (in-situ condition). The XAFS can provide information that is not accessible by other techniques for characterization of materials, particularly catalysts and related surfaces. Furthermore, XAFS can provide a molecular-level approach to the study of reaction mechanisms for the understanding of catalysts and development of new catalysts. A number of synchrotron radiation facilities have been planned to be built in Asian countries in addition to the high-brilliant synchrotron radiation facilities under construction in the USA, Europe, and Japan. The applications of XAFS have now expanded to catalytic chemistry and engineering, surface science, organometallic chemistry, materials science, solid-state chemistry, geophysics, etc. This book caters to a wide range of researchers and students working in the domain or related topics.