This collection of readily reproducible techniques for repairing mammalian DNA contains fourteen entirely new chapters and many extensively revised chapters. The methods presented cover cytogenetic analysis, measuring the cellular response to ionizing radiation, detecting single-strand (nicks) and double-strand DNA breaks, detecting the presence of "adducted" bases in DNA, and preparing mismatch repair (MMR) plasmid substrates. Among the highlights are excellent coverage of both base excision repair (BER) and nucleotide excision repair (NER), useful assays for identifying and quantifying UV-induced DNA lesions and DNA breakage, gene therapy, environmental mutagenesis and cancer, and gene targeting.