For this second edition of their much praised Cytochrome P450, the editors have collected accounts of the essential core techniques that use the latest methodologies for the investigation of P450s. Highlights include protocols for spectral analysis and purification of P450s, enzymatic assays of P450s and flavin-containing monooxygenases (FMOs), expression of P450s and FMOs in heterologous systems, and the production and use of antipeptide antibodies. Additional chapters contain readily reproducible techniques for the transfection of hepatocytes for gene regulation studies, P450 reporter gene assays, in situ hybridization, and analysis of genetic polymorphisms. Although the emphasis is on P450s of mammalian origin, many of the readily reproducible methods described are suitable for P450s from any source.