Principles of Animal Extrapolation addresses the conceptual basis for animal extrapolation and provides an abundance of documentation that illustrates how these principles may be applied in the selection of the more appropriate models and in the interpretation of toxicological studies. The book analyzes and documents each specific biological cause of interspecies differences in susceptibility to toxic agents, including differences in absorption, gut flora, tissue distribution, metabolism, mechanisms and efficiencies of repair, and excretion. The problem of the heterogenicity of the human population is addressed through several chapters that assess the availability and prospects of developing predictive animal models for normal humans, as well as selected potential high-risk groups. Other topics presented in this book include the biological basis of regulatory actions involving attempts to extrapolate from exceptionally high exposure levels to realistic values, especially carcinogens; an assessment of genotoxicity tests, their ability to predict carcinogenicity in whole animals, and the manner in which they should be used by regulatory agencies; birth defects; and predicting the risk of human teratogenesis. Principle of Animal Extrapolation is essential for environmental toxicologists. It also provides valuable information to biomedical scientists (especially those involved in drug development and testing) and regulatory personnel in agencies such as the EPA, the OSHA, the NIOSH, and the FDA.