Interest in scaling laws has grown since the beginning of the 21st century. In both the social sciences and the natural sciences, there is continued astonishment at the increasing inequalities between large and small cities. While social indicators are often thought of as linear measures, in terms of per capita quantities, economies of scale allow us to take account of sublinear relationships or superlinear relationships (amplifications), achieved according to the size of cities. Given the dual challenge facing cities in terms of ecological transition and technological innovation, it is crucial to inform urban policies about the effects of their size on the qualities of cities. Scaling Laws and Urban Systems provides an overview of this new knowledge in terms of growth and adaptation capacities, resource extraction or environmental pollution, as well as the sustainability of the living conditions that cities now offer to the majority of the world s population.
