It is difficult to imagine a world without cities. More people around the globe now live in urban rather than rural areas, and almost everyone has traveled to a city, seen cityscapes on television, or used goods manufactured in factories. Yet for most of human history there were no urban centers. Indeed, there were no villages until about 14,000 years ago, and up until a few decades ago the great majority of people lived in small communities. To determine whether the spread of some early civilizations were earlier moments of globalizations, we need to first appreciate what life was like in villages before cities emerged. Almost all the people you knew were neighbors, virtually everything that you owned or consumed came from nearby, and your ideas about how the world worked came from family traditions. The emergence of cities transformed people's lives by dramatically increasing interregional interaction. Who you knew, what you ate, and what you thought changed after the urban revolution.

The possible links between urbanism, interaction, and the spread of what has often been called civilization have been of long-standing interest within anthropology, sociology, and archaeology (Schortman and Urban 1998; Trigger 1989: 150–5). One of the earliest authors to make these connections was Emile Durkheim. In his classic work, The Division of Labor in Society (1984 [1893]), he argued that there were two extremes in social integration – mechanical and organic solidarity.