In the first half of the twentieth century, Alfred Stieglitz did more to introduce modern art to an American public than—arguably—any other single individual. Even for all of his fame as a photographer, he will probably be best remembered as an art dealer, a profession whose commercial activities he disdained. In an era when ego and greed have earned many gallerists the kind of reputation usually reserved for used-car salesmen, it is remarkable that a major American museum—the National Gallery of Art in Washington, DC, no less—would organize an exhibition that acknowledges