With the world population expected to swell by almost two and a half billion people by 2050, new and existing cities must accommodate many of them. Depending on the choices we make, this could exacerbate existing problems like pollution, congestion, lack of infrastructure or public services, and marginalization of the poor. Or, if we rethink urban living and its governance, it could equally be an opportunity to develop the low-carbon, resource-efficient and socially just cities called for in the New Urban Agenda. This assessment report from the International Resource Panel, explores this transition through urban planning, investment in resource efficient infrastructure technologies and entrepreneurial governance. Note: Lead and contributing authors other than MS and MH are listed alphabetically.