Pernick and Wilder explain that, in the 1970s, clean technology was considered “alternative,” the province of back-to-the-land lifestyle advocates, altruistic environmentalists, and lab scientists on research grants. Such technology was in an early stage of development, was too expensive, it did not have widespread political support, and very few large, established companies were embracing the sector. Even at the start of the 21st century, the term "clean tech" was not yet in the financial or business community’s vocabulary. But now, throughout much of the world, in trends large and small, there is "the beginning of a revolution that is changing the places where we live and work, the products we manufacture and purchase, and the development plans of cities, regional governments, and nations around the globe."