The son of a wealthy textile merchant, Henri Cartier-Bresson (1908-2004) studied painting at André L’hote's academy in Montparnasse in 1927, and soon thereafter entered the bohemian world of the Parisian avant-garde. In 1931, he began to use a camera and to make photographs that reveal the influence of both Cubism and Surrealism—bold, flat planes, collage-like compositions, and spatial ambiguity—as well express an affinity for society's outcasts and the back alleys where they lived and worked. Within a year, he had mastered the miniature 35mm Leica camera and had begun traveling in Italy, Spain, Morocco, and Mexico, developing what would become one of the hallmarks of twentieth-century photographic style. Although he was influenced by such photographers as Eugène Atget and André Kertész (1894–1985), his photographic fusion of form and content was groundbreaking. In 1952 he published the landmark monograph, The Decisive Moment.
Cartier-Bresson was drafted into the French army in 1940. He was taken prisoner by the Germans but escaped on his third attempt and joined the French Resistance. In 1946, he assisted in the preparation of a "posthumous" show of his work organized by the Museum of Modern Art in New York in the mistaken belief that he had been killed in the war. The following year he founded the Magnum photo agency with Robert Capa (1913–1954), David "Chim" Seymour (1911–1956), and others, and spent the next twenty years on assignment, documenting the great upheavals in India and China, and also traveling to the Soviet Union, Cuba, Canada, Japan, and Mexico. He left Magnum in 1966 and devoted himself primarily to painting and drawing.