Walter Savitch is Professor Emeritus of Computer Science at the University of California at San Diego. He received his PhD in mathematics from the University of California at Berkeley in 1969. Since that time he has been on the faculty of the University of California in San Diego (UCSD). He served as director of the UCSD Interdisciplinary PhD program in Cognitive Science for over ten years. He has served as a visiting researcher at the Computer Science departments of the University of Washington in Seattle and and at the University of Colorado in Boulder, and has been a visiting scholar at the Centrum voor Wiskunde en Informatica in Amsterdam.