American photography critic, conservationist, and editor who was an important contributor to the development of the photograph book as an art form.

She attended Smith College and was a member of the Art Students League of New York. Her career began in 1943, when she became acting curator of the photography department at the Museum of Modern Art, New York City, substituting for her husband, Beaumont Newhall, the photography historian and founder of the department, while he was in military service.

Among Newhall's 22 books are Time in New England (1950), with photographs by Paul Strand, and the biography Ansel Adams (Adams, Ansel) (1963). Her long collaboration with Adams produced the landmark classic of conservationism This Is the American Earth, published by the Sierra Club in 1961 in the “oversize” format that she helped to pioneer. It is considered her most important work.