John Muir (1838 – 1914) was an influential naturalist, author, environmental philosopher, and advocate for the preservation of wilderness areas in the United States. In 1869, Muir travelled to California and spent a long time in the area that is now the Yosemite National Park. This narrative takes the form of a hiking guide filled with adventure. Muir was a master of description, providing stirring portraits of the area's wildlife, waterfalls, valleys, meadows, giant sequoias groves, lakes, mountains, , and glaciers. About Yosemite Falls, he writes, "At the top of the fall they seem to burst forth in irregular spurts from some grand, throbbing mountain heart."