The article reviews the book 'Risk Quantitation and Regulatory Policy,' D. G. Hoel, R. A. Merrill, and F. P. Perera (eds), published by Cold Spring Harbor Laboratory, Cold Spring Harbor, New York. The book is another volume in the continuing series of Banbury Conferences devoted to the in-depth exploration of a single topic. This particular book (Volume 19) provides an outstanding summary of the state of the art/science of quantitative risk assessment (QRA). The authors explore the underlying assumptions and techniques of QRA and point out where the science ends and the art begins.