Exploration of some o f their shared properties leads us to view organisations as purposeful social systems which are characterised by a functional division o f labour with respect to the ends o f the system as a whole. But it is perhaps the differences among organisations that are striking-differences not only in their goals or functions, but in their technologies, their structures, systems of authority, and so on. Unable to say much that is both useful and true with respect to all organisations, and sensitive to the limitations o f generalising from case studies of single organisations or parts o f organisations, a number of organisation theorists have concentrated instead on generating typologies of organisations which will allow us to make systematic comparisons between different classes o f organisations and perhaps venture into the construction of theory o f the ‘middle range' . This is the explicit aim of Etzioni, whose typology is described below. A further alternative is the approach that is taken in the recent book o f Blau and Schoenherr,1 who study and compare the properties o f a very large number of organisations in order to illuminate the relationships between structural properties such as size, differentiations, formalisation of rules, bureaucratic rigidity, complexity and so on. The use o f a typology may be thought of as a variant o f this comparative method in which variations in organisational characteristics are related to a classificatory variable, on the basis o f which different types of organisation have been identified.