Donald R. Prothero is Chairman and Associate Professor of Geology at Occidental College, Los Angeles, California. He has been a Guggenheim and NSF Fellow, a Fellow of the Linnean Society, and in 1991 received the Schuchert Award of the Paleontological Society for outstanding paleontologist under the age of 40. He has authored or co-edited seven books, including The Evolution of Perissodactyls (Oxford Univ. Press, 1989, co-edited with R.M. Schoch), Interpreting the Stratigraphic Record (W.H. Freeman, 1990), Eocene-Oligocene Climactic and Biotic Evolution (Princeton Univ. Press, 1992, co-edited with W.A. Berggren), Evolution of the Earth (McGraw-Hill, 1993, with R.H. Dott), Paradise Lost: The Eocene-Oligocene Transition (Columbia Univ. Press, 1993), Horns, Tusks, Hooves and Flippers: The Evolution of Hoofed Mammals and Their Relatives (Princeton Univ. Press, 1993, with R.M. Schoch), and The Terrestrial Eocene-Oligocene Transition in North America (Cambridge Univ. Press, 1994, co-edited with R.J. Emry). He is a Technical Editor of Journal of Paleontology and Adjunct Editor of Paleobiology.