Donald R. Prothero is professor of geology at Occidental College. He is the author of The Eocene-Oligocene Transition: Paradise Lost (Columbia, 1993), Terrestrial Eocene-Oligocene Transition in North America, and Bringing Fossils to Life: An Introduction to Paleobiology. Linda C. Ivany is assistant professor of earth sciences at Syracuse University. Elizabeth A. Nesbitt is Curator of Invertebrate Paleontology at the Burke Museum and a member of the geological sciences faculty at the University of Washington. Donald Prothero earned his M.A. (1978), M.Phil. (1979), and Ph.D. in 1982 from Columbia University. His career has included appointments at several prestigious institutes of higher learning, most recently as a Lecturer in Geobiology at the California Institute of Technology and as an Associate Professor of Geology at Occidental College. Donald has been the recipient of numerous honors and awards, including a Guggenheim Fellowship, and is an active member of many geological societies.