The analysis of urban development of the past twenty years presented in this maiden edition of the World Cities Report shows, with compelling evidence, that there are new forms of collaboration and cooperation, planning, governance, finance and learning that can sustain positive change. The Report unequivocally demonstrates that the current urbanization model is unsustainable in many respects. It conveys a clear message that the pattern of urbanization needs to change in order to better respond to the challenges of our time, to address issues such as inequality, climate change, informality, insecurity, and the unsustainable forms of urban expansion.