In the images that Alfred Stieglitz called Equivalents, the great photographic pioneer experimented with his camera and darkroom techniques to create abstract fields of light and dark. Thereafter, the transformation of events recorded from the natural world into abstract photographs became one of the 20th century’s most vital visual traditions. Alfred Stieglitz and the Equivalent: Reinventing the Nature of Photography combines the remarkable Equivalent photographs in the Stieglitz-O’Keeffe archive at Yale’s Beinecke Rare Book and Manuscript Library with images selected from the Yale University Art Gallery’s rich permanent photography collection to take a revisionist look at a familiar photographic tradition, tracing that tradition from Stieglitz’s early innovations to contemporary creative achievements. The placement of Stieglitz’s Equivalents within a theoretical framework sheds new light on the history of photography.