The First volume gives an overview of the enzymes involved in DNA synthesis and modification; the second volume deals with the RNA-enzymes. Although the major emphasis of the book is on eukaryotic enzymes, a separate chapter dealing with prokaryotic DNA repair enzymes has been included to discuss the major advances in this field in recent years. There are two separate chapters on RNA polymerases to provide a comprehensive coverage of the enzymes from lower eukaryotes, plants and higher eukaryotes.