ARY L. GOLDBERGER, M.D., is a pioneer in the application of concepts from nonlinear dynamics ("chaos theory") to human physiology and human organizations. His recent work focuses on the dynamics of human creativity and on health and disease in complex organizations. He is Director of the Margret and H.A. Rey Institute for Nonlinear Dynamics in Physiology and Medicine at Beth Israel Deaconess Medical Center, Professor at Harvard Medical School and Program Director of the NIH/NCRR Research Resource for Complex Physiologic Signals.