There are some stories so compelling, so rich and unexpected, even the most creative of writers couldn’t dream them up.  Street photographer Vivian Maier’s is one of them. For several decades, Ms. Maier served as a beloved nanny to privileged families in the wealthy suburbs of Chicago, after arriving to the bustling city in 1956. For years, her friends knew nothing of her hidden talent, until historian John Maloof recovered more than 100,000 negatives and countless hours of Super 8 footage from her storage locker.

As it turns out, Maier’s instincts far surpassed the field of caregiving. She had an impeccable eye and insatiable appetite for taking pictures — for capturing the candid and visceral moments of Chicago’s citizens, cityscapes, and busy streets.  Since her passing in 2009, her prolific body of work has been exhibited globally and locally, and was recently shown at LA’s Merry Karnowsky Gallery. In the years since her discovery, she’s been recognized as one of the most influential street photographers of the 20th century, alongside the likes of Diane Arbus, Robert Frank, and Henri Cartier-Bresson. “Finding Vivian Maier” takes a glimpse inside this very private, silently observant woman’s life, with anecdotes and insights provided by those who knew her. You can watch the trailer for the documentary, debuting this month at the Toronto Film Festival, below.

By Jane Helpern