This extensive volume offers 130 presentations that examine the relevance of N-nitroso compounds to human cancer. Significant advances are presented on the measurement of exposures to N-nitroso compounds and on possible links with several common human cancers. The contributions are from scientists in a wide range of disciplines, and cover clinical and epidemiological studies, tobacco/betel-quid carcinogenesis, endogenous formation, measurement of exposure, metabolism, reaction with cellular macromolecules, molecular mechanisms, and biological effects. This is the ninth in a biennial series of symposia, which is widely recognized to be the leading source in the field.