Vivian Maier was an unknown nanny until her photographs were discovered in a Chicago storage locker in 2007. Suddenly, she rocketed to posthumous fame, as critics and viewers were blown away by the way she captured ordinary workers, women, and marginalized groups. A new biography of Maier's life dives into her early years, her time in New York, France, and Chicago, and includes over 400 of her photographs, many published for the first time. Author Ann Marks joins us to discuss her acclaimed biography, Vivian Maier Developed.