International cooperation has never been more needed, but the current system of "aid" is outdated and ineffective. The Future of Aid calls for a wholesale restructuring of the aid project, a totally new approach fit for the challenges of the 21st century: Global Public Investment. Across the world, billions of people are struggling to get by in unequal and unsustainable societies, and international public finance, which should be part of the answer, is woefully deficient. Engagingly written by a well-known expert in the field, The Future of Aid calls for a series of paradigm shifts: From a narrow focus on poverty to a broader attack on inequality and unsustainability. From seeing international public money as a temporary last resort, to valuing it as a permanent force for good. From North-South transfers to a collective effort, with all paying in and all benefitting. From outdated post-colonial institutions to representative decision-making. From the othering and patronizing language of "foreign aid", to the empowering concept of Global Public Investment. Ten years ago, in The Trouble with Aid, Jonathan Glennie highlighted the dangers of aid dependency and the importance of looking beyond aid. Now he calls for a revolution in the way that we think about the role of public money to back up our ambitious global objectives. In the wake of the Covid-19 crisis, it is time for a new era of internationalism.