Action takes place at a given time and place. As a science of human action, economics is, therefore, just as much about the spaces where real action occurs as it is about real time. The implications of real time for social order is better recognized than the significance of “action space.” The living city is the principal locus of action space and enabler of social change as well as the source of fundamental concepts in economic theory. Just as a loss of density and diversity in cities tends to retard dynamic discovery and development, the turn in economic theory in the mid-20th century toward static equilibrium reflected a move from an urban-based to a plantation-based conception of the economy—from the city to the farm. Some recent developments in network theory, game theory, and geography, however, can be interpreted as a re-urbanization of economics.