The Green Transition to net-zero carbon emissions is the defining challenge of our age. It would require a large-scale transformation of our consumption and production patterns to turn the existing physical capital stock—high-carbon-emitting buildings, vehicles, power plants, and factories—into a low-carbon, resource-efficient foundation for a future sustainable economy. However, one question remains unsettled: where should the money come from to pay for it? The premise of this research group is that past episodes of financing large-scale transformations hold valuable lessons for future attempts to bring about deep socio-economic change. In an age of constrained national budgets, what kind of past policies can we bring into the present? This is important to know because historically states had to muster all available physical and financial resources to deal, for instance, with wartime mobilisation. Similarly, in periods of post-war reconstruction, capital-starved states have had to think creatively of ways of making finance available for the slow-burning process of rebuilding the physical stock and society at large. What insights do these episodes hold for our current challenge of achieving the Green Transition?