The first 5 chapters on the theory of human health risk assessment, are written or co-written by the editor-in-chief/author, Dr. Paustenbach. The second part of the book assembles the expertise of more than fifty authorities from fifteen different fields and includes 7 case studies written or co-written by Dr. Paustenbach. Of the approximately 50 cases studies, 40 of these studies will be new, and 10 will have extensive updates as compared to the previous edition. The result is in an authoritative guide to risk assessment that provides the theoretical underpinning of risk assessment that in turn is grounded in actual real-world case studies of sites or issues that address a wide range of human and ecological hazards."The overall quality of the text, with the emphasis on providing transparency in the calculations, the quantitative description of uncertainty in the risk estimates, and the importance of proper risk characterization should help ensure that better quality risk assessments are conducted in the coming years. Students and practitioners will benefit significantly from the work of Dr. Paustenbach and his colleagues."Foreword by William K. Reilly, former administrator of the U.S. Environmental Protection Agency