Our world is becoming more urban. More than fifty percent of the global population now lives in cities, which poses new challenges for sustainable development. This book integrates theory and methods of sustainability assessment with concepts from systems science to provide guidelines for assessing the sustainability of urban systems. It discusses different aspects of urban sustainability, from energy and housing, to mobility and health, covering social, economic and environmental factors, as well as the various stakeholders and actors involved. The book argues for the need to find models and solutions in order to design sustainable cities of the future in light of the complexity of urban social life. Including diverse case studies from the developed and developing world, this book provides a useful reference for researchers and students from a broad range of disciplines working in the field of sustainability, as well as for environmental consultants and policy makers.