In Nature, there is little chemical waste; nearly every atom is a resource to be utilized by organisms, ensuring that all the available matter remains in a perpetual cycle. By contrast, human systems of energy production and manufacturing are linear; the end product is waste. In Brave Green World, Chris Forman and Claire Asher show what our linear systems can learn from the efficient circularity of ecosystems. They offer an unblinkered yet realistic and positive vision of a future in which we can combine biology and manufacturing to solve our central problems of waste and pollution.