Donald D. Cowan is a Distinguished Professor Emeritus (1999) and Adjunct Professor in the School of Computer Science, University of Waterloo, Waterloo, Ontario. He received a BASc in Engineering Physics from the University of Toronto in 1960 and an MSc and PhD from the University of Waterloo in Applied Mathematics in 1961 and 1965 respectively. He joined the Faculty of the University of Waterloo in 1961 and was the first chair of the Dept. of Applied Analysis and Computer Science, now the School of Computer Science (1967 to 1972) and also served as Associate Dean of Graduate Studies in the Faculty of Mathematics (1974 to 1978). Donald D. Cowan is Director of the Computer Systems Group, a computer science research group at the University of Waterloo in which he has been involved since the early 1960's.