Leading biologists and philosophers of biology discuss the basic theories and concepts of biology and their connections with ethics, economics, and psychology, providing a remarkably unified report on the "state of the art" in the philosophy of biology. AUTHORS: Gereon Wolters is professor emeritus of philosophy and history of science at the University of Konstanz and director of the philosophical archive. He is coeditor of Concepts, Theories, and Rationality in the Biological Sciences and Logic, Language, and the Structure of Scientific Theories, among other books. James G. Lennox is professor of history and philosophy of science at the University of Pittsburgh. He is the author of Aristotle: On the Parts of Animals I?IV and Aristotle's Philosophy of Biology: Studies in the Origins of Life Science. Lennox is coeditor of Philosophical Issues in Aristotle's Biology; Being, Nature, and Life in Aristotle: Essays in Honor of Allan Gotthelf; and Concepts, Theories, and Rationality in the Biological Sciences.