This is the first book to directly address the physics of urban sustainability, and how urban sustainability may be modelled and optimized. Starting with an introduction to the importance and key aspects of the topic, it moves on to a detailed consideration of the urban climate and pedestrian comfort. Comprehensive techniques for the modelling and optimization of urban metabolism are then described, together with means for defining sustainability as the fitness function to be optimized. It ends with an eye to the future of sustainable urban design and the means available to urban designers and governors to help them to secure a more sustainable urban future. This book will be invaluable both in informing the next generation of urban planners, architects and engineers, and as a tool for current professionals that will directly contribute to the effectiveness of their work by allowing them to more successfully measure and model urban sustainability.