H. Frederik Nijhout received his Ph.D. from Harvard University in 1974. He is a professor of biology at Duke University, where he has been since 1977. He studies the roles of hormones in control of growth and metamorphosis in insects, and is particularly interested in the developmental and physiological mechanisms that control switches between alternative developmental pathways. He also continues to enjoy his work on the development and evolution of butterfly wing patterns. Address: Department of Biology, Duke University, Durham, NC 27708. Internet: hfn@duke.edu