In the United States of America, the year 1864 saw the publication of two books which laid the foundation for Romantic and Utilitarian conservation traditions in America. The posthumous publication of Henry David Thoreau's Walden established the grandeur of unspoiled nature as a citadel to nourish the spirit of man. A very different book from George Perkins Marsh, Man and Nature, later subtitled "The Earth as Modified by Human Action", catalogued his observations of man exhausting and altering the land from which his sustenance derives.