In 2007, a Chicago man named John Maloof bought a box of photo negatives at an auction house for a couple of hundred dollars. The box turned out to be a cache of incredible street photographs from an artist no one had ever heard of. Those who knew her only knew her as a curmudgeonly, enigmatic nanny. Since then, Maloof has gone on to be her champion: printing and archiving thousands of her photos, creating two books on her work, and holding shows around the world. He’s also co-directed a movie about her called Finding Vivian Maier. Madeleine speaks to Maloof as part of a series of interviews this week with the filmmakers behind this year’s Oscar-nominated documentaries.