Book excerpt: Cancer Precursors is a groundbreaking, multidisciplinary text containing a comprehensive overview of methodological issues associated with the study of pre-cancerous conditions, as well as reviews of the contributions of descriptive, analytical, and molecular epidemiological research to knowledge about cancer precursors at specific anatomical locations. The research focuses on the early natural history of cancers, by helping to define the etiology of precursor lesions, improving the means of detecting them either directly or via testing of surrogate biomarkers, and by elucidating the role of remote causes leading to the early onset of such lesions.