In this chapter, the theories of management and organizational behaviour provide an outline of the way in which thinking has evolved on management and organizational behaviour since the late nineteenth century. It looks at the various schools of thought, the principles behind them, and their good points and their bad points. The chapter concentrates on the work of two main writers, researchers, thinkers and theorists of that time, Frederick Taylor and Henri Fayol. Both were engineers who were involved in industry during the development of assembly line production and it was that sort of process that their theories were particularly geared towards. Henri Fayol was the first of the modern management writers to put forward a theoretical analysis of what managers have to do and by what principles they might try to do it. Taylors view was that, when properly applied, the principles of scientific management led to increases in efficiency, productivity and profitability.