Abstract
A core concern of all planning theory is properly linking knowledge to action. Using this core concern as the base for analysis, this paper examines the nature of underlying differences among contemporary schools of planning. The analysis centres on four general concerns of planning: its guiding purpose, the role of the planner, knowledge of the future, and knowledge of the public interest. The results highlight areas of debate among schools of planning thought, and suggest a separation between knowledge and action. In turn, the method of analysis demonstrates that using similarities as themes that cut across schools of planning thought helps to advance a theoretical understanding of planning as a social phenomenon.