? ?Charge carrier transfer reactions have been widely acclaimed to be very important as they play a pivotal role in photocatalytic processes. The fundamental study of the dynamics of the charge transfer processes is important in the design of new photocatalysts as well as for the industrialization of the photocatlytic processes. During the past decades, extensive investigations have been performed concerning the study of the kinetics and of the mechanistic details of the interfacial electron transfer processes at the semiconductor/water interface using the laser photolysis and the pulse radiolysis technique. ?I invite the world-recognized scientists who are specialists in photocatalysis to contribute specific chapters to this monograph.This is to cover the major aspects in photocatalysis from fundamentals to applications. The main objective of the present book is to study the dynamics of the charge carrier transfer processes induced by light at TiO2 nanoparticle/liquid (metal ions, organic molecules, O2, ...) interfaces and to elucidate the mechanistic models for a better understanding of photocatalytic reactions.