Peter H. Raven, Ph.D., is director of the Missouri Botanical Garden and Engelmann professor of botany at Washington University at St. Louis. He oversees the garden's internationally recognized research program in tropical botany--one of the world's most active in the study and conservation of imperiled tropical habitats. Raven's botanical research and work in the area of tropical conservation have earned him numerous honors and awards, including a MacArthur Fellowship. He has written 17 textbooks and more than 400 articles, and he is a member of th National Academy of Science and the National Research Council.