ABSTRACT
Understanding what goes on in the real world presents us with numerous problems, and this is particularly true when we consider the complexity of life in the world's cities. Indeed, a complete understanding of the social, economic and political processes of city life is beyond the capacity of any man. To help grapple with these problems, and to build up some understanding of urban phenomena, social scientists have developed a number of models, or theories, which, though analytic abstractions, hopefully help us to identify some of the key aspects, or variables, in city life, and to indicate the possible relationships between these variables. These models, or theories, range from relatively simple checklists of factors to be identified or questions to be asked, through explanations of a limited phenomenon, to broad general models which seek to identify all the important or key variables and to suggest how they are related to each other in a complex fashion. All seek to simplify the real world and reduce it to essentially manageable proportions, and all vary in their scope and level of explanation.
