J. Baird Callicott is University Distinguished Research Professor of Philosophy and formerly Regents Professor of Philosophy at the University of North Texas. He is co-Editor-in-Chief of the Encyclopedia of Environmental Ethics and Philosophy and author or editor of a score of books and author of dozens of journal articles, encyclopedia articles, and book chapters in environmental philosophy and ethics. Callicott has served the International Society for Environmental Ethics as President and Yale University as Bioethicist-in-Residence, and he has served the UNT Department of Philosophy and Religion Studies as chair. His research goes forward simultaneously on four main fronts: theoretical environmental ethics; comparative environmental ethics and philosophy; the philosophy of ecology and conservation policy; and biocomplexity in the environment, coupled natural and human systems (sponsored by the National Science Foundation). Callicott is perhaps best known as the leading contemporary exponent of Aldo Leopold's land ethic and is currently exploring an Aldo Leopold Earth ethic in response to global climate change. He taught the world's first course in environmental ethics in 1971 at the University of Wisconsin-Stevens Point. His teaching at UNT includes graduate and undergraduate courses in ancient Greek philosophy and ethical theory in addition to environmental philosophy.