“Theoretical approaches have their place and are, I suppose, essential but a theory must be tempered with reality.”

The empirical or case approach : The members of this school study management by analyzing experience, usually through cases...
The interpersonal behavior approach: This approach is apparently based on the thesis that managing involves getting things done through people, and that therefore the study of management should be centered on interpersonal relations...
The group behavior approach : This approach is ... primarily with behavior of people in groups rather than with interpersonal behavior...
The cooperative social system approach : A modification of the interpersonal and group behavior approaches has been the focus of some behavioral scientists on the study of human relationships as cooperative social systems...
The sociotechnical systems approach : One of the newer schools of management identifies itself as the sociotechnical systems approach...
The decision theory approach : This approach to management theory and science has apparently been based on the belief that, because it is a major task of managers to make decisions, we should concentrate on decision making...
The systems approach ; ... the systems approach to the study and analysis of management thought...
The mathematical or "management science" approach : There are some theorists who see managing as primarily an exercise in mathematical processes, concepts, symbols, and models...
The contingency or situational approach : ... the contingency approach to management.
The managerial roles approach :... popularized by Henry Mintzberg [1973, 1975]...
The operational approach : The operational approach to management theory and science, a term borrowed from the work of P. W. Bridgman [1938, pp. 2-32], attempts to draw together the pertinent knowledge of management by relating it to the functions of managers...
The nature of the operational approach can perhaps best be appreciated by reference to Figure 1. As this diagram shows, the operational management school of thought includes a central core of science and theory unique to management plus knowledge eclectically drawn from various other schools and approaches...
Source: "The Management Theory Jungle Revisited," 1980, p. 177-182