S. R. Nagpaul was visiting Professor of Mathematics at Ohio University 1983-1984 and 1999-2004. He was formerly Head of the Department of Mathematics at St. Stephen's College, Delhi. Dr. Nagpaul received his Ph.D. from Harvard University under G. Birkhoff. He is a coauthor of two other texts: BASIC ABSTRACT ALGEBRA, Cambridge University Press, and LINEAR ALGEBRA, New Age Publisher. His special interest is in Discrete Mathematics.