The environmental movement of the 1960s and 1970s overshadows a second, less heralded intellectual development that took place at the exact same time: the birth of “ecological economics.” A cluster of nonconforming economists in this period drew on the fledgling science of ecology to rethink many of the assumptions of neoclassical economics, with its “growthmania,” general indifference toward pollution and ecosystem destruction, and dogmatic belief that “tastes and preferences” are innate in humans rather than culturally shaped. What emerged was a new school of thought that integrated ecological concerns into an essentially capitalist economic framework. These iconoclasts brought together the dual nature of the Greek word “oikos” (literally: household), which is the etymological root of both “economics” and “ecology.” They asserted that the human “household” could not exist without a healthy and functional natural environment. This has become the essential insight of economic sustainability—the second “E” of sustainability: that the world needs economic systems that exist harmoniously with nature (and which promote social equality and justice). Those who practice the economics of sustainability in the present day— William E. Rees, Mathis Wackernagel, Peter Victor, Tim Jackson, Richard Heinberg, and many others—are the heirs of these early critics who challenged the hegemony of business-as-usual economics. First-wave ecological economics shares the readability of the classic environmental works discussed in the previous chapter. The main authors associated with ecological economics—E. J. Mishan, E. F. Schumacher, Kenneth Boulding, Howard T. Odum, Nicholas Georgescu-Roegen, Herman Daly, Amory Lovins, and the members of the shadowy-sounding Club of Rome—went out of their way to write nontechnical books that were meant to appeal to the average-educated reader. Collectively, these authors ask deep and penetrating philosophical questions: What is the point of endless economic growth? What are the environmental costs of a wasteful and fossil-fuel-addicted consumer society? What is the best way to measure the well-being of a society? What is the role of economics in ensuring that human society remains within its ecological limits and avoids overshoot and collapse? How can nature, society, and the economy be studied as a single system?