Since the 1970s, Herman Daly has been the world's leading proponent of a steady-state economy. Throughout his career, Daly has published several books and articles on the subject. He has also helped founding the Center for the Advancement of the Steady-State Economy (CASSE). He has received several prizes and awards in recognition of his work. According to two independent comparative studies of American Daly's steady-state economics versus the later, competing school of degrowth from continental Europe, no differences of analytical substance exist between the two schools; only, Daly's bureaucratic — or even technocratic — top-down management of the economy fares badly with the more radical grassroots appeal of degrowth, as championed by French political scientist Serge Latouche (see below). The premise underlying Daly's concept of a steady-state economy is that the economy is an open subsystem of a finite and non-growing ecosystem (earth's natural environment). The economy is maintained by importing low-entropy matter-energy (resources) from nature; these resources are put through the economy, being transformed and manufactured into goods along the way; eventually, the throughput of matter-energy is exported to the environment as high-entropy waste and pollution. Recycling of material resources is possible, but only by using up some energy resources as well as an additional amount of other material resources; and energy resources, in turn, cannot be recycled at all, but are dissipated as waste heat. Out of necessity, then, any subsystem of a fixed nongrowing system must itself at some point also become nongrowing. Daly argues that nature has provided basically two sources of wealth at man's disposal, namely a stock of terrestrial mineral resources and a flow of solar energy. An 'asymmetry' between these two sources of wealth exist in that we may — within some practical limits — extract the mineral stock at a rate of our own choosing (that is, rapidly), whereas the flow of solar energy is reaching earth at a rate beyond human control. Since the Sun will continue to shine on earth at a fixed rate for billions of years to come, it is the terrestrial mineral stock — and not the Sun — that constitutes the crucial scarcity factor regarding man's economic future. Daly points out that today's global ecological problems are rooted in man's historical record: Until the Industrial Revolution that took place in Britain in the second half of the 18th century, man lived within the limits imposed by