ABSTRACT
The term 'system of cities', as used here, encompasses all those individual urban units – however defined – in a country or large region which are economically linked to one or more other individual urban units in the same country or large region. The specialized information pertaining to costs, prices, supply, demand, and technological and other matters which influences the decisions underlying city-system growth and development is virtually never universally available. Spatial biases in the circulation of private information have traditionally arisen because of the time and monetary costs associated with acquisition. Migration and local and non-local employment multiplier effects, two of the most elemental event classes involved in the past and present growth and development of city-systems, can be approached through an elaboration of the 'population-' and 'activity'-system concepts used by Hagerstrand and his associates in their effort to design a 'time-geography' model of society.
