Open spaces and built structures are two main components of the city structure; their quality determines overall quality. In the historic urban quarters, open spaces have special character, image and sense of place compared to the recently developed ones. It must be quest why public open spaces in the historic urban quarters have higher quality than the recently developed ones. Hypothesis has been developed: "Design principles play an effective role on the formation/evolution of public open spaces in the past . This book, therefore, provides a new method of analysis to measure the quality of public open spaces in the historic urban quarters; takes design principles as indicators. Besides, it provides: a summary on the history of cities by reviewing Kostof, Mumford and Benovolo s approaches with special emphasis on the evolution, development, components and characteristics of the walled cities and list of public open space design principles that is derived from various researchers studies. It targets researches, designers, planners interested in the history of cities; walled cities; typology, design and quality of public open spaces.