Historian Donald Worster examines man's often ambivalent relationship with nature in a series of essays illuminating individuals and points of view that have shaped land practices and policies over the past two centuries--even before Ernst Haeckel coined the term ecology in 1866. At one pole are the Romantics and Arcadians who seek cooperation and harmony with nature. Their views are sometimes joined by latter-day animists or organicists who see all living forms as an integrated whole or who believe in transcendent ""vital forces."" Countering those views are the imperialist man-must-dominate nature attitudes originally fostered by the Judeo-Christian tradition and reinforced by capitalism and the growth of science and technology. American policies of land ""management,"" predator ""control,"" and the plow-that-broke-the-plains stem from man-conquering-nature tradition. Worster is especially good in showing how these beliefs culminated in the disaster of the Dust Bowl and the dirty Thirties, in turn giving rise to revisionist thinking about the environment. The present ""Age of Ecology"" is dominated by paradigms from physics and economics. Nature is seen as an ""ecosystem whose variables can be measured in terms of energy equations (calories expended or produced) or in terms of economic notions of producers versus consumers. At the same time other voices--particularly associated with such groups as the Sierra Club--revive the ideas of a land ethic and the need to consider moral values in determining man's relation to the environment. How effective they will be is moot, for the historian, while sympathetic, remains detached. This is a scholarly book on an absorbing subject, not often treated at the level of the general reader. The quality of writing varies. At times Worster is elegant and lyrical, especially in the chapters on Thoreau. Elsewhere he can be repetitive or pedantic or, in the case of Darwin, somewhat one-dimensional. The content and the approach--historical/philosophical--are greatly to be commended. They raise both consciousness and conscience.