Sarah Greenough, senior curator and head, department of photographs, National Gallery of Art. Many of the artists associated with the photographer and gallery director Alfred Stieglitz explored abstract portraiture in the early decades of the twentieth century. These artists included Marius de Zayas, Arthur Dove, Marsden Hartley, Francis Picabia, Man Ray, and Stieglitz himself. But beyond a few watercolors made in 1917, Georgia O’Keeffe is not known to have extensively investigated this genre. In this lecture, held on January 22, 2017, at the National Gallery of Art, Sarah Greenough suggests that O’Keeffe made many more abstract portraits than have been previously identified, which have, as she herself admitted in the early 1970s, “slipped into the world as abstractions.”