John Hagel III is a principal at the Silicon Valley office of McKinsey & Company, Inc., and a leader of the firm's Interactive Multimedia Practice. His work is primarily with clients in the electronics, telecommunications, and media industries, with a focus on strategic management and performance improvement. Prior to joining McKinsey, he served as senior vice president for strategic planning at Atari; as president of Sequoia Group, a systems house selling turnkey computer systems to physicians; and as a consultant with the Boston Consulting Group. Mr. Hagel is the author of a number of legal and business books and articles. His most recent piece, written with Harvard Business School professor Jeffrey F. Rayport, was ""The Coming Battle for Customer Information,"" which appeared in the January/February 1997 issue of the Harvard Business Review.