Dr. Mark L. Gillenson has been practicing, researching, teaching, writing, and, most importantly, thinking, about data and database management for over twentyfive years, split between working for the IBM Corporation and being a professor in the academic world. While working for IBM, he designed databases for IBM's corporate headquarters, consulted on database issues for some of IBM's largest customers, taught database management at the prestigious IBM Systems Research Institute in New York, and conducted database seminars throughout the United States and on four continents. In one such seminar...