The growing impact of regulations on the economy has led both Congress and the administration to search for new ways of reforming regulation. One of the central issues in the debate is the use of benefit-cost analysis in environmental, health, and safety regulation. In an effort to develop a consensus view on that controversial subject, the American Enterprise Institute, the Annapolis Center, and Resources for the Future cosponsored a meeting of many of the leading economists in the field. This primer highlights the set of consensus principles that emerged from that meeting. It should be required reading for policymakers who wish to understand both the strengths and the limitations of benefit-cost analysis in the development, design, and implementation of regulatory reform.