John Muir ( April 21, 1838 - December 24, 1914) also known as "John of the Mountains," was a Scottish-American naturalist, author, environmental philosopher and early advocate of preservation of wilderness in the United States. His letters, essays, and books telling of his adventures in nature, especially in the Sierra Nevada of California, have been read by millions. His activism helped to preserve the Yosemite Valley, Sequoia National Park and other wilderness areas. The Sierra Club, which he founded, is a prominent American conservation organization. The 211-mile (340 km) John Muir Trail,...