Nan Goldin is an American artist and activist who rose to prominence in the 1980s together with her diaristic physique of labor, “The Ballad of Sexual Dependency,” which has been introduced as an expansive slideshow, a photograph guide, and a movie. Katherine A. Bussard, the Peter C. Bunnell Curator of Photography at the Princeton University Art Museum, discusses the landmark photograph guide because it celebrates its fortieth anniversary.