Ralph Abraham has been Professor of Mathematics at the University of California at Santa Cruz since 1968, and has held teaching posts at Berkeley, Columbia, Princeton, and many visiting positions in Europe and Asia. He is the author of more than 20 texts, with eight books currently in print.  He has been a consultant on chaos theory and its applications in numerous fields (medical physiology, ecology, mathematical economics, psychotherapy, etc.) and is an active editor for the technical journals World Futures, and the International Journal of Bifurcations and Chaos. www.ralph-abraham.org