Book excerpt: Surface Science of Photocatalysis, Volume 32, summarizes significant findings on the surface science behind various classic and novel photocatalysts for energy and environmental applications, with special emphasis on important surface/interface processes in photocatalysis, such as interfacial charge transfer, function of co-catalysts, and adsorption over photocatalyst surface. This book timely and systematically reviews the state-of-the-art of the surface science in semiconductor-based photocatalysis, serving as a useful reference book for both new and experienced researchers in this field.