William Henry Fox Talbot and his picture machine -- Defining art against the mechanical, c. 1860 -- Julia Margaret Cameron transfigures the glitch -- The fog of beauty, c. 1890 -- Alfred Stieglitz moves with the city -- Stalking chance and making news, c. 1930 -- Frederick Sommer decomposes our nature -- Pressing photography into a modernist mold, c. 1970 -- John Baldessari plays the only game in town.