Can green capitalism save the planet? Is it even trying? Not when the very logic of the capitalist system pits it against Earth's life support systems, as the Japanese philosopher Kohei Saito demonstrates in one of the most astonishing bestsellers of recent times. Drawing on cutting-edge research across multiple disciplines, Saito shows how nothing but a transformation of our economic life can save us from climate collapse. Karl Marx himself reached this breakthrough at the end of his life, long before climate change had even begun. What few people realise is that it radically altered his vision of proletarian revolution. Now that we are entering our own end-game, we must grasp Marx's final lesson before it is too late. If we are to avoid the three terrible prospects of climate fascism, climate Maoism or mere anarchy, the future must belong to degrowth communism, a fair and humane existence within the limits of nature. There is no alternative: the endless acceleration of capital has run out of road. We must slow down. A surprise hit on publication in Japan, Slow Down inspired a generation of activists, and will unleash the imaginative power necessary to create a better world in the age of climate crisis.