9319994 Berliant The location of consumers, producers and marketplaces is in a state of transition. We need tools, models and conceptual frameworks to address the most important questions concerning the economic role of cities. Why do cities form where they do? What are the driving forces behind the formation and growth of cities? The answers to these questions are clearly relevant to urban policy decisions, but before these applications can be made, relevant theories that answer these basic questions must be developed. This research attempts to fill part of this need by extending two basic models of location to the point of obtaining a conceptual framework for analysis and then using this framework to answer some of the critical questions.The analysis treats prices and quantities of goods produced and consumed as endogenously determined. The endogenous location of consumers, producers, and especially marketplaces will be highlighted. After obtaining existence of a stable (equilibrium) state of the system and studying its efficiency properties for each model, the work is extended to analyse the effects of changes in policy variables. The empirical part of the study uses simulation exercises to find equilibrium for special cases. ***
