Recently discovered street photographer Vivian Maier has some 100,000 photographs to her name. She shot from the 1950s-1990s, mostly in Chicago and mostly with a Rolleiflex camera. John Maloof, a real estate agent who discovered her photographs, keeps a blog where he posts her photos. There is currently a Kickstarter campaign to fund a feature-length documentary about her life and work.
Maier, who passed away in 2009 at the age of 83, was an intensely private person who wouldn't show her pictures to anyone, hence why they were not unearthed until now.
Also, check out this video about her Jeff posted.