As a major defence against environmental damage to cells DNA repair is present in all organisms including bacteria, yeast, drosophila, fish, amphibians, rodents and humans. DNA repair is involved in processes that minimise cell killing, mutations, replication errors, persistence of DNA damage and genomic instability. Abnormalities in these processes have been implicated in cancer and ageing. This book presents leading-edge research from around the world in this frontal field.