Starting in the late eighteenth century when machine power was substituted for human power, a point in history known as the industrial revolution, it became more economical to manufacture goods in factories rather than at home. These large efficient factories needed someone to forecast demand, ensure that enough material was on hand to make products, assign tasks to people, direct daily activities, and so forth. That “someone” was a manager: These managers would need formal theories to guide them in running these large organizations. It wasn’t until the early 1900s, however, that the first steps toward developing such theories were taken.