Book excerpt: A thorough understanding of cellular and molecular mechanisms involved in the individual expression of toxic effects provides an important tool for assessment of human health risk. New aspects, major advances, and new areas in molecular and cellular biology and toxicology demand updated sources of information to elucidate the functional mechanics of human toxicology. Mechanistic Toxicology: The Molecular Basis of How Chemicals Disrupt Biological Targets, Second Edition retains the accessible format of the original to present the general principles that link xenobiotic-induced toxicity with the molecular pathways that underlie these toxic effects. Extensively illustrated, this book forms a conceptual bridge between multiple events at the molecular level and the determinants of toxicity at the physiological and cellular level. Specific examples of drugs, environmental pollutants, and other chemicals are carefully chosen to illustrate and highlight the fundamental mechanisms of toxicity at different toxicokinetic and toxicodynamic levels. The book includes references and review articles at the end of each chapter, as well as boxed text for relevant review information on biological, biochemical, molecular, and toxicological background. Linking molecular pathways to more general biomedical contexts, the author ensures that the reader is not lost in the details and instead receives a broad understanding of the processes underlying xenobiotic toxicity. New in the Second Edition Updated chapters Types of toxic responses Disruption of signal transduction by xenobiotics Disruption of mitochondrial function Novel mechanisms derived from systems toxicology