Alfred Stieglitz
Alfred Stieglitz was born in New Jersey in 1864 (died in 1946). He went to engineering school in Germany but later returned to New York to pursue photography. His wife, Georgia O'Keeffe, was a famous painter, and he often photographer naked photos of her. Alfred worked hard to make photography an accepted form of art, as it wasn't in 1864. He eventually created a magazine called the Camera Notes, which was an amazing photography magazine.
Henri Cartier Bresson was born in 1908 (died in 2004 (wow he lived awhile)) and was seen as a very influential photography figures. His work started around 1930, and helped to define the creative potential in modern photography. He spent most of World War Two as a prisoner of war, however after that he Robert Capa in the founding of Magnum photo agency. He took a lot of street photography, and also took photos of people when they were unaware that they were being photographed.