Francisco J. Varela, Ph.D., was Fondation de France Professor of Cognitive Science and Epistemology at the ecole Polytechnique and the Institute of Neuroscience of Paris. He is also the author of "Principles of Biological Autonomy. "Humberto R. Maturana, Ph.D., is a biologist who teaches at the University of Chile. He is also co-author with Dr. Varela of "Autopoiesis and Cognition: The Realization of the Living."