What Is Planning Theory and Why Is It Important?

Two long-debated questions are these. Firstly, “What is planning theory?”. Secondly, “Why do planning theory?”. This chapter briefly addresses these questions by revisiting the long-standing problem of the relation between planning theory and practice. The chapter adopts the view that every action or practice implies, either implicitly or explicitly, a theory. Clearly, either we can leave all the theoretical assumptions imbued in planning practice undiscussed or we can consider them critically; this is “doing (planning) theory”. In short, one of the main tasks of planning theory—though obviously not the only one—should be to foster critical debate on the theoretical assumptions that inevitably underlie planning practice.