Ansel Adams (1902-1984) was an American photographer and environmentalist known for his black and white landscape photographs of the American West, particularly Yosemite National Park. He was also an advocate for conservation and preservation of wilderness areas.

Adams' photographs are renowned for their sharp focus, precise tonality, and high contrast, achieved through his use of large-format cameras and careful darkroom techniques. His most famous images include "Moon and Half Dome," "Clearing Winter Storm," and "Monolith, The Face of Half Dome."

In addition to his photographic work, Adams was a co-founder of Group f/64, a group of photographers who advocated for a "pure" photographic style that emphasized sharp focus and detailed texture. He also wrote several instructional books on photography and co-founded the first academic department of photography in the United States, at the California School of Fine Arts (now the San Francisco Art Institute).

Adams was also a passionate environmentalist and used his photography to raise awareness of the need to protect and preserve natural areas. He served on the board of directors of the Sierra Club, and his images were used to promote the organization's conservation campaigns.

Adams is considered one of the most important photographers of the 20th century and his work has had a lasting impact on the art and practice of photography.