Steven R. Williams is Professor of Economics at the University of Illinois in Urbana-Champaign, where he has also served as head of the economics department. He earned a B.A. from Kenyon College in 1976 and M.S. and Ph.D. degrees from Northwestern University in the field of mathematics in 1977 and 1982, respectively. After postdoctoral appointments at the Institute for Mathematics and its Applications at the University of Minnesota and at Bell Laboratories, he served as a faculty member at Northwestern University before moving to the University of Illinois. Professor Williams has published art...