John Muir 
Steep Trails / California, Utah, Nevada, Washington, Oregon, the Grand Canyon [PDF ebook] 

John Muir 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.
Spanning nearly three decades of John Muir’s work and showing the great conservationist author at his best, this collection of two dozen magazine articles and letters focuses on his travels to the lakes, canyons, and mountains of the American West, including the Great Salt Lake, the San Gabriel Mountains, Mount Rainer, and the Grand Canyon.