Thinking Like a Mountain is a short essay by Aldo Leopold. It appears in the collection of essays A Sand County Almanac. (Oxford University Press, 1966). It was a very influential work back then, introducing to many the idea of thinking not as a human only (anthropocentric), but as a part of all life (ecocentric). He had seen that when the wolves are gone, the animals they prey on increase in number and the forest too is gone after a little while.
Aldo Leopold: Thinking Like a Mountain . (text of article)
The Aldo Leopold Foundation's mission is to foster the land ethic through the legacy of Aldo Leopold.
The University of Wisconsin has an online public archive of his work, along with correspondence and related materials carefully retained over the years by his mother, his wife, and other family members and professional associates.