WILLIAM STALLINGS has made a unique contribution to understanding the broad sweep of technical developments in computer networking. He has authored 15 titles, and counting revised editions, a total of 35 books on various aspects of this subject. He has five times won the annual Text and Academic Authors Association award for the best computer science textbook. He is an independent consultant whose clients have included computer and networking manufacturers and customers, software development firms, and government research institutions. Dr. Stallings holds a Ph.D. from M.I.T. in Computer Science. He maintains the computer science student support site at WilliamStallings.com/StudentSuport.html. All of his Prentice Hall titles can be found at the Prentice Hall Web site .