It is not the purpose of this book to be a supplement to the earlier work bearing the same title. The intent is to demonstrate the usefulness of organic photochemical reactions as powerful tools in organic synthesis. In contrast to the preceding monograph, an exhaustive compilation of all preparative applications of photochemical reactions has become virtually impossible in this vigorously expanding field. I have therefore tried to select the (subjectively) most representative examples of synthetic utile reactions with a strong preference for more recent publications and reviews. In this context the literature was covered up to June 1981.