Charles H. Smith is professor emeritus at Western Kentucky University. Most recently, he is coeditor of Dear Sir: Sixty-Nine Years of Alfred Russel Wallace Letters to the Editor. James T. Costa is executive director of the Highlands Biological Station and professor of biology at Western Carolina University. Most recently, he is the author of Darwin's Backyard: How Small Experiments Led to a Big Theory. David Collard is professor emeritus of economics at the University of Bath where he has headed up the Economics Group since 1978. He has published research on the economics of altruism, welfare, and taxation. Some of his contributions to the history of economics are collected in Generations of Economists.