In the past two decades considerable theological energy has been expended in the construction of various ecological theologies and spiritualities. Process theologians, ecofeminists, and theologians of creation, earth, nature, ecology, and land have been elucidating religious perspectives that they hope will help transform human attitudes toward nature and the environment. These writers have sought to reorient Christianity away from anthropocentric views that claim human dominion over nature, premillennial expectations that embrace the destruction of this world, soteriological preoccupations that focus on individual salvation, and otherworldly assumptions that foster alienation from the earth and nature. Some sanguine observers have seen this recent ferment as the greening of American theology or even the greening of the American churches. At the same time, intellectual historians have paid increasing attention to the history of Western ideas about nature and have debated at length the impact of Christianity's theological heritage on the environmental crisis. Specifically, a number of historians have constructed a genealogy of American conservationist and preservationist thought by tracing out a line that includes, among others, George Catlin, Henry David Thoreau, George Perkins Marsh, John Muir, Aldo Leopold, and Rachel Carson.