The report presents the first assessment of the resources required at a global scale for the coming wave of urbanization. Using material flow analysis, the analysis of urban form and city organization, the assessment of the potential contribution of known sustainable technologies, as well as case study methodology, it reveals the possibility of an alternative, resource-efficient urban management strategy. The report identifies the proliferation of the sustainability-oriented ‘urban experiments’ as a basis for a new form of resource-efficient urbanism. This emergent mode of urban governance can be aligned with the potential of networks of knowledge-based economies that will change industrial activity in cities over the coming decades. The report seeks to address the complex interrelationships between (1) urban population growth and demographic change, (2) spatial change and development (with particular reference to (de-)densification), (3) infrastructure planning and development, and (4) resource flows into, through and out of urban systems, and consequently the complex interrelationships between cities and the wider ecosystems within which they are embedded. It presents urban resource flows as being key to understanding what it will take to promote a transition from resource-intensive urban metabolism towards alternatives that manage resources more carefully.