Daniel A. Wren on Principles of management

“George R. Terry (1909–1979) was the first to call his book Principles of Management... Terry’s elements included planning, organizing, directing, coordinating, controlling, and leading human efforts. Later, Terry combined the functions of directing and leading human efforts into an ‘‘actuating’’ function and stopped treating coordinating as a separate function. Terry defined a principle as ‘‘a fundamental statement providing a guide to action,’’ and his principles, like Fayol’s, were lighthouses to knowledge and not laws in a scientific sense.”

“Harold D. Koontz (1908–1984) and Cyril O’Donnell (1900–1976) of the University of California at Los Angeles defined management as "the function of getting things done through others." They furthered Fayol’s ideas and sought to provide a conceptual framework for the orderly presentation of the principles of management. According to Koontz and O’Donnell, managers were known by the work they performed, which was planning, organizing, staffing, directing, and controlling. These authors pointed out that, although some authorities maintained that these functions were exercised in the sequence given, in practice managers actually used all five simultaneously. They stressed that each of these functions contributed to organizational coordination. Coordination, however, was not a separate function itself but was the result of effective utilization of the five basic managerial functions. Koontz and O’Donnell offered a number of principles: in organizing, for example, "the principle of parity of authority and responsibility" and "the principle of unity of command"; in planning, "the principle of strategic factors"; and so on. The Koontz and O’Donnell text became an enduring, integral part of the search for a systematic body of management knowledge.”