books.google.com - The essays presented in this volume describe a phenomenon so widespread in human time and space that its importance is easily overlooked. City walls shaped the history of warfare; the mobilization of manpower and resources needed to build them favored some kinds of polities over others; and their massive...https://books.google.com/books/about/City_Walls.html?id=S7dUv-1Ql2oC&utm_source=gb-gplus-shareCity Walls