He has held visiting positions in Amsterdam, Paris, Warwick, Barcelona, Basel, and Florence, and is the author of more than 20 texts. He has been active on the research frontier of dynamics -- in mathematics since 1960, and in applications and experiments since 1973. 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. In 1975, he founded the Visual Mathematics Project at the University of California at Santa Cruz, which became the Visual Math Institute in 1990, with its popular World Wide Web site since early 1994. He has performed works of visual and aural mathematics and music (withAmi Radunskaya and Peter Broadwell) since 1992.