Karl S. Matlin is a cell biologist and professor in the Department of Surgery and a member of the Committee on Conceptual and Historical Studies of Science at the University of Chicago. He is coeditor, most recently, of Visions of Cell Biology: Reflections Inspired by Cowdry's "General Cytology, " also published by the University of Chicago Press. Jane Maienschein is University Professor in the School of Life Sciences at Arizona State University and fellow and director of the History and Philosophy of Science Project at the Marine Biological Laboratory in Woods Hole, Massachusetts. She is coeditor, most recently, of The Ark and Beyond: The Evolution of Zoo and Aquarium Conservation, also published by the University of Chicago Press. Rachel Ankeny is professor of history at the University of Adelaide, Australia, and honorary visiting professor in the College of Social Science and International Studies (Philosophy) at the University of Exeter, UK.