"The various schools of or approaches to management theory that I identified nearly two decades ago, and called "the management theory jungle," are reconsidered. What is found now are eleven distinct approaches, compared to the original six, implying that the "jungle" may be getting more dense and impenetrable. However, certain developments are occurring which indicate that we may be moving more than people think toward a unified and practical theory of management."

“The Decision Theory School : Another approach to management theory, undertaken by a growing and scholarly group, might be referred to as the decision theory school. This group concentrates on rational approach to decision-the selection from among possible alternatives of a course of action or of an idea. The approach of this school may be to deal with the decision itself, or to the persons or organizational group making the decision, or to an analysis of the decision process. Some limit themselves fairly much to the economic rationale of the decision, while others regard anything which happens in an enterprise the subject of their analysis, and still others expand decision theory to cover the psychological and sociological aspect and environment of decisions and decision-makers.”

“The Mathematical School ; Although mathematical methods can be used by any school of management theory, and have been, I have chosen to group under a school those theorists who see management as a system of mathematical models and processes. Perhaps the most widely known group I arbitrarily so lump are the operations researchers or operations analysts, who have sometimes anointed themselves with the rather pretentious name of "management scientists." The abiding belief of this group is that, if management, or organization, or planning, or decision making is a logical process, it can be expressed in terms of mathematical symbols and relationships. The central approach of this school is the model, for it is through these devices that the problem is expressed in its basic relationships and in terms of selected goals or objectives.”

“Although students of management would readily agree that there have been problems of management since the dawn of organized life, most would also agree that systematic examination of management, with few exceptions, is the product of the present century and more especially of the past two decades.”

“Organization charts are subject to important limitations. A chart shows only formal authority relationships and omits the many significant informal and informational relationships.”

“The Management Process School : This approach to management theory perceives management as a process of getting things done through and with people operating in organized groups. It aims to analyze the process, to establish a conceptual framework for it, to identify principles underlying it, and to build up a theory of management from them. It regards management as a universal process, regardless of the type that the environment of management differs widely between enterprises and levels. It looks upon management theory as a way of organizing experience so that practice can be improved through research, empirical testing of principles, and teaching of fundamentals involved in the management process.”

“The management theory jungle is still with us... Perhaps the most effective way would be for leading managers to take a more active role in narrowing the widening gap... between professional practice and our college and university business .”