Art dealers, until the advent of Gagosian and his ilk, rarely received much recognition outside of the rarified circles of the art world. A few are admired for having supported the vanguard: in New York, Samuel Kootz and Betty Parsons for the Abstract Expressionist generation, or Leo Castelli, André Emmerich, and Richard Bellamy for the next wave. A century earlier, in Paris, Paul Durand-Ruel is credited with discovering and creating a market for the Impressionists, after falling in love with the work of the then-unknown “New Painters”—a lifelong passion to which he devoted most of his life and his money. Durand-Ruel’s compatriot Ambroise Vollard played a significant role in the lives and reputations of artists ranging from Paul Cézanne to Pierre Bonnard to Pablo Picasso, and he sat for portraits by many of them. In pre–World War I Paris, Daniel-Henry Kahnweiler championed the radical work of Picasso, Georges Braque, and their colleagues before the term “Cubism” was even coined, while back in New York Alfred Stieglitz helped to introduce Americans first to French vanguard art and then to the most adventurous artists on this side of the Atlantic.

While hardly household names, Durand-Ruel and Vollard, Kootz and Parsons, Kahnweiler and Stieglitz are familiar to anyone interested in modern art. But the name of the influential director of New York’s Downtown Gallery, Edith Halpert, conspicuously missing from this list, would probably elicit a polite “who?” from all but the obsessed. Despite her crucial impact on the careers of such