MARK V. LOMOLINO is a Professor in the Department of Environmental and Forest Biology at SUNY College of Environmental Science and Forestry, Syracuse. He is cofounder and past President of the International Biogeography Society. Dr. Lomolino received the American Society of Mammalogists Award and serves on the editorial advisory boards for Biological Conservation and Global Ecology and Biogeography. LAWRENCE R. HEANEY is Curator and Head of the Division of Mammals at The Field Museum in Chicago. Dr. Heaney studies the ecology and evolution of mammals on the islands of Southeast Asia and