Twenty centuries of “progress” have brought the average citizen a vote, a national anthem, a Ford, a bank account, and a high opinion of himself, but not the capacity to live in high density without befouling and denuding his environment.—Aldo Leopold, Game Management (1933)1 Aldo Leopold was a forester, a professor of wildlife management, and an advocate for wilderness preservation who achieved national standing in each endeavor. Generations of readers have admired the lyrical quality of Leopold’s writing. The author of three hundred publications, Leopold conveyed complex scientific ideas in a succinct and accessible style. A Sand County Almanac, posthumously published in 1949, eventually emerged as a touchstone of the environmental movement and sold more than two million copies. “The Land Ethic,” the book’s capstone essay, extended the ethics of…