 The schools of thought derive from Taylor, Henri Fayol, Lyndall Urwick, Herbert A. Simon, and others endeavored to prescribe and expound norms to show what managers must or should do.With the arrival of Mintzberg, the question was no longer what must or should be done, but what a manager actually does during the day.More recently, in his 2004 book Managers Not MBAs, Mintzberg examined what he believes to be wrong with management education today.