Urbanization and population growth have been proceeding at an exponential rate for the past two hundred years. Consequently, the future of humanity and our long-term sustainability are inextricably linked to the fate of our cities. Cities are simultaneously hubs for innovation, ideas, and culture, as well as engines of wealth creation, centers of power, and drivers of entrepreneurship and social transformation. But they are also the prime source of crime, pollution, disease, and energy and resource consumption. Cities are the problem, but they are also the solution. What do physics and biology have to teach us about achieving long-term urban resilience and sustainability? Theoretical physicist Geoffrey West makes the case for a broad, quantitative, predictive approach for understanding the dynamics, organization, and growth of the metropolis. Geoffrey West