Volume 1 provides the reader with a basic overview of the field of toxicology. The volume is divided into four sections: 1) introduction, 2) toxicokinetics, 3) mechanisms of toxicity, and 4) risk assessment. The volume provides an in-depth coverage of the field of toxicokinetics including exposure assessment, routes of exposure of toxicants, and distribution, biotransformation, and excretion of toxicant. Dosimetry modeling, including physiologically based pharmacokinetic models, and extrapolation modeling are covered. The volume also covers key mechanisms associated with toxicity/carcinogenicity of chemicals. Concepts of risk assessment are also discussed in this volume. The contents of Volume 1 lays the ground work for subsequent volumes of the Comprehensive Toxicology series where different aspects of the field of toxicology are extensively discussed.