Ansel Adams (1902-1984) was a pioneering American photographer and environmentalist known for his stunning black-and-white photographs of the American West, particularly Yosemite National Park. He developed the Zone System, a technique for determining optimal film exposure and development, and helped establish photography as a fine art. Adams co-founded the photography department at the Museum of Modern Art and Group f/64, which promoted sharp-focus photography. His advocacy was instrumental in expanding the National Park System and advancing environmental conservation. His most famous works include "Monolith, The Face of Half Dome" and "Moonrise, Hernandez, New Mexico," which remain iconic representations of the American landscape.