In 1935, Aldo Leopold bought an abandoned farm in the sand counties along the Wisconsin River near Baraboo. Leopold sensed promise in the land, and with his wife and five children nursed the land back to health. They cleaned out the chicken coop and affectionately called their new family retreat "The Shack." Leopold kept detailed notes during the process of land restoration, and then wrote the essays published in 1949 as A Sand County Almanac. His writings present an eloquent plea for development of what he called "the land ethic"--the belief that although people have the right to use the bounty of the land, they must "limit freedom of action in the struggle for existence" while accepting responsibility to treat the soils, waters, plants, and animals in ways that restore and nurture their well-being. Leopold's life shaped his land ethic. He emerged as a leader of the conservation movement of his time, challenging the notion that land was merely property to be used--and used up if necessary--in the pursuit of economic wealth. More than fifty years after publication of A Sand County Almanac, Leopold's voice remains at the core of modern conservation ethics. This article describes the life and works of Aldo Leopold. (Contains 42 notes.)