This 5-cent commemorative stamp issued by the United States in 1955 honors naturalist and conservation pioneer John Muir, widely regarded as the “Father of the National Parks.” The bi-color design features Muir’s portrait set against towering sequoia trees of Yosemite, symbolizing his lifelong advocacy for wilderness preservation. Issued during the mid-20th-century conservation movement, the stamp reflects America’s growing environmental awareness. Well-centered mint examples with strong color contrast between the green and brown printings are particularly attractive to thematic collectors of conservation, environment, and American history.