This groundbreaking manual provides step-by-step methods covering all aspects of the cellular response to DNA damage, including nucleotide and base excision repair, DNA strand break repair, mismatch repair and tolerance mechanisms. The techniques are based on eukaryotic model systems in widespread use that have made, or have the potential to make, important contributions to our understanding of cellular responses to DNA damage in relation to mutagenesis, carcinogenesis, and the cell cycle. The majority of the chapters are devoted to mammalian cells, which reflects the allocation of resources in the DNA repair field. Non-mammalian model systems are also covered, and specifically yeasts, drosophila, Xenopus and plants, the latter of which are of vital interest given the problem of ozone depletion and consequent loss of UV protection. The practical methods offered in this book will encourage the transfer of methodologies between model systems and stimulate the reader's development of new approaches in the study of DNA damage and repair.