Martha A. Sandweiss began her career as a curator of photographs, later became the director of a college art museum, and now, as professor of American studies and history at Amherst College, teaches a broad array of classes in American studies, visual culture, public history, and the history of the American West. She has a deep interest in how historians can use visual images as primary sources to answer a broad range of questions about the past. She is interested in how images themselves can be interrogated as complex historical documents and can convey ideas that cannot be learned by other means. In recent years, she has been exploring an entirely different topic: how one prominent American explorer, geologist, and writer lived a secret double life in late nineteenth-century New York. His story has led her to a larger exploration of race, class, and identity in Americaâ€™s largest city.