This book takes a bold epistemological approach to address the fundamental questions that urban design has faced since its inception – questions concerning its legitimacy, definition, nature, content, purpose, theory, methods, jurisdiction and above all its knowledge base. The appropriate level of urban design – global or local – is another critical and emerging question discussed. At the end, an integrative theory of urban design is introduced, on the basis of which a set of principles is developed for application by practicing urban designers. These principles are presented at three essential levels: general, global and local-Iranian. is intended to dispel many of the ambiguities still troubling urban design as a discipline and profession.