Last week, the technology and operations management faculty at Harvard Business School convened for its annual "Research Day," where members reflect on the direction in which things are headed for our department and the field. Bob Hayes, one of the monumental figures in the history of operations management and now an emeritus member of the business school faculty, described how the field had evolved in, what he called, "bursts of energy," starting with the enthusiasm for quantitative methods that flowed from efforts to get supplies past German U-boats in World War II.