Herbert Spencer had a major influence on developments in sociology in the 1870s and 1880s. A ‘positivist’ in the Comtian tradition, his principal contribution was to develop in a more detailed and extensive manner the implications of the biological analogy for sociology. The functionalist paradigm has provided the dominant framework for academic sociology in the twentieth century and accounts for by far the largest proportion of theory and research in the field of organisation studies. Building upon the concepts of holism, interrelationship between parts, structure, functions and needs, the biological analogy has been developed in diverse ways to produce a social science perspective firmly rooted in the sociology of regulation. Georg Simmel’s interest in sociology at a micro-level of analysis led to many insights with regard to the dynamics of social life. As far as the development of the functionalist paradigm is concerned, it is through the notion of equilibrium that Pareto has had most influence.