Cook was born in New York City. She took graduate courses in portraiture and documentary photography from 1973 to 1975, then earned her B.A. from Barnard College in 1978. After graduation, Cook studied privately with Ansel Adams from 1978 to 1984, becoming his last protégée.
Cook's work is included in numerous private and museum collections, including at the Metropolitan Museum of Art and the Museum of Modern Art in New York, the J. Paul Getty Museum in Los Angeles, the Museum of Fine Arts in Boston, the Museum of Fine Arts in Houston, Bibliothèque Nationale and Musée d’Art Moderne in Paris, and the National Portrait Gallery in Washington. She has exhibited in Paris, New York, Martha’s Vineyard, Tucson, and Santa Monica.
Her work has appeared in numerous publications, including regular work for The New Yorker, as well as in articles and television documentaries. She has also published books of her work, including Fathers and Daughters, and Justice: faces of the Human Rights Revolution.