John F. Ahearne is an adjunct scholar for Resources for the Future and an adjunct professor of engineering@Duke University. He has served as commissioner and chairman of the U.S. Nuclear Regulatory Commission, system analyst for the White House Energy Office, U.S. Deputy Assistant Secretary of Energy, U.S. Principal Deputy Assistant Secretary of Defense, executive director of Sigma Xi and director of Sigma Xi Ethics Programs. He is a member of the National Academy of Engineering and the American Academy of Arts and Sciences, a fellow of the American Physical Society, the Society for Risk Analysis, and AAAS and chair of the advisory committee of the National Academy of Engineering Center for Engineering, Ethics and Society. He received a Ph.D. in physics from Princeton University. His professional interests include reactor safety, energy issues, resource allocation and public policy management. Address: Sigma Xi, P.O. Box 13975, Research Triangle Park, NC 27709. E-mail: ahearne@sigmaxi.org