In the 60,000 years since people began colonising the continents, a recurring feature of human civilisation has been mobility - the ever-constant search for resources and stability. Seismic global events - wars and genocides, pandemics and plagues - have only accelerated the process. The map of humanity isn't settled, not now, not ever. As climate change tips toward full-blown crisis, economies collapse, governments destabilise and technology disrupts, we're entering a new age of mass migrations - one that will scatter not just the dispossessed but all of us. Parag Khanna provides an illuminating and authoritative vision of the next phase of human civilization - one that is both mobile and sustainable.