This book offers an up-to-date guide to the concepts, procedures, statistical methods, and models used to assess human exposure to environmental chemicals. Noting that exposure assessment is a comparatively new discipline of the environmental sciences, the book aims to encourage its use as a powerful tool for measuring actual levels of exposure and determining whether interventions are needed to protect public health. With this goal in mind, the book gives researchers expert advice on the design and conduct of studies, the interpretation of findings, and the best methods for ensuring the reliability and reproducibility of results. Throughout, emphasis is placed on the ways in which well-designed exposure assessments can enhance the practical value of findings from traditional epidemiological and toxicological investigations. The book has twelve chapters. The first six cover conceptual and methodological issues. Chapter one introduces basic concepts used in exposure assessment, and describes direct and indirect methods of measuring or estimating actual exposure and determining whether intervention is required. The uses of human exposure data are covered in chapter two, which explains how studies of human exposure can reduce the uncertainty of estimates used in epidemiology, risk assessment, and risk management. Chapter three considers several generic study designs and approaches, and compares their advantages and limitations. Chapter four, on statistical methods, discusses selective applications of descriptive and inferential statistics, using data on lead exposure as an example. Subsequent chapters review methods for the collection and application of time-use data, and introduce the principles, methods, and data requirements of exposure modelling.