This is an influential book about the emergence of urban areas before the advent of industrialization. Dr. Sjoberg describes the developments that contributed to the concentration of human populations in relatively small areas that were geographically removed from the fields in which food was produced, and which we would today recognize as towns and cities. The most important of these was the development of technologies, particularly the cultivation of high yield grains, that made possible the production of a food surplus and in turn permitted the specialization of some of the members of a population in nonagricultural activities. A second key development was the discovery of methods for alloying metals to produce weapons that were durable and effective enough to both permit the subordination of large areas to economic exploitation and concomittantly to make efficient strategies of defense necessary.Prior to the publication of this book, the existence and significance of urban concentrations in the preindustrial era, which after all encompasses most of urban history to date, was largely overlooked in social theory.