John Muir was a Scottish-American preservationist, naturalist, and environmental philosopher. He is best known for his work in the conservation of wilderness areas in the United States, particularly Yosemite National Park. Muir was an influential figure in the early environmental movement and is often referred to as the 'Father of the National Parks'. He was also a prolific writer, publishing several books on the subject of nature and the environment. Muir's legacy continues to this day, with his name being used to promote environmental causes and organizations.