Photosensitization and phoatalysis refer to processes by which permanent chemical transformations are induced on substrates (organic/inorganic) by radiation to which the substrates themselves are transparent. Such transformations can be highly specific, very efficient, and occur under mild conditions. Herein lies the power of phohemical methods for possible applications in the field of conversion and storage of solar energy. This book provides a recent survey of the progress in this important area in catalysis, with an emphasis on inorganic complexes and organometallic compounds as the key light aborbers. The book is organized in three parts: fundamentals, followed by applications. Discussions cover a wide variety of photosensitized or phoatalyzed reactions: decomposition of water, reduction of CO and CO; spectral sensitization in photoelectrochemical cells; transformations (oxidation, reduction, isomerization, hydrogenation, dehydrogenation, carbonylation, etc.) of organics such as alkanes, alkenes, alcohols, etc. In view of the variety of systems (sensitizers, substrates) and the topics covered, the volume is unique in the field of phohemistry and will appeal to academic and industrial researchers in various subdisciplines of chemistry, material science and catalysis.