ABSTRACT
This chapter argues the case for an urban-system perspective – indeed a continental or even global perspective – and approach to contemporary urbanization. It outlines the concept of the urban system, and reviews its evolution, and its strengths and weaknesses. The chapter describes, with special reference to North America, those trends that are redefining the urban process writ large and reordering the challenges posed for researchers and government agencies. It also reviews questions of the definition, measurement and classification of urban settlements and urban systems, the importance of links to urban nodes outside the system, and the information gaps confronting researchers. The concept of an 'urban system', or system of cities, is based on notions of interaction and interdependence. The chapter examines a series of issues relating to the concepts, statistical building blocks and basic information required to analyze urban systems under diverse national and global conditions, systems that are themselves undergoing rapid transformation.
