Historical perspective on the development of the EMEA Guideline and subsequent ICH M7 Guideline -- ICH M7 -assessment and control of DNA reactive (mutagenic) impurities in pharmaceuticals to limit potential carcinogenic risk -- Control strategies for mutagenic impurities -- Use of structure-activity relationship (SAR) evaluation as a critical tool in the evaluation of the genotoxic potential of impurities -- Evolution of quantitative structure-activity relationships ((Q)SAR) for mutagenicity -- Toxicity testing to understand the mutagenicity of pharmaceutical impurities -- Compound- and class-specific limits for common impurities in pharmaceuticals -- Genotoxic threshold mechanisms and points of departure -- Mutagenic impurities -assessment of fate and control options -- N-nitrosamines -- Conditions potentially leading to the formation of mutagenic impurities -- Strategic approaches to the chromatographic analysis of mutagenic impurities -- Analysis of mutagenic impurities by nuclear magnetic resonance (NMR) spectroscopy -- Addressing the complex problem of degradation-derived mutagenic impurities in drug substances and products.