In documenting the lives of female impersonators, middle-class New York families, nudists, and mentally ill patients, Diane Arbus loved to seek out differences. "Nothing is ever the same as they said it was," she wrote. "It's what I've never seen before that I recognize." But she transcended other documentary photographers of her day through her extraordinary insight and empathy—in her insistence on presenting her subjects as exactly equal to the viewer. With 200 prints, contact sheets, and notebooks, Diane Arbus: Revelations, opening at the San Francisco Museum of Modern Art on October 25, will be the first major show devoted to Arbus since New York's Museum of Modern Art retrospective in 1972, a year after she committed suicide at the age of 48.