Dr. Jeffrey Shallit is Associate Professor of Computer Science at the University of Waterloo, in Ontario, Canada. He received his Ph.D. in mathematics from the University of California, Berkeley in 1983, under Manuel Blum. He taught at the University of Chicago and Dartmouth College prior to his present position, and has been a visiting professor at the University of Wisconsin and the Universite de Bordeaux, France. His research interests are algorithmic number theory and formal languages. His book with Eric Bach, Algorithmic Number Theory, will be published in 1995 by MIT Press. He can be reached by email as shallit@graceland.uwaterloo.ca.