IAN STEWART, Ph.D., has written or coauthored numerous books, including Does God Play Dice?, Fearful Symmetry, Collapse of Chaos, and Nature’s Numbers. In addition, he writes the "Mathematical Recreations" column in Scientific American, serves as mathematics consultant to New Scientist, and is a regular contributor to Discover and The Sciences. In 1995 Dr. Stewart received the Royal Society of England’s Michael Faraday Medal for outstanding contributions to the public understanding of science.