“I Have No Mouth, and I Must Scream,” Harlan Ellison titled one of his science fiction short stories. That’s as perfect an expression of an artist’s experience of “quiet desperation” as has ever been put on the page.

Vivian Maier had no mouth, no access to the famous, the powerful, taste-makers. But she had an eye. And once she applied it to her Rolleiflex camera — in New York, Chicago and elsewhere — she captured life in all its candid American glory, beginning in the 1950s.

Thousands and thousands of images she snapped, untold reels of home movies she shot. She even tape recorded herself, and others she questioned, when cassettes caught on.

But none of this ever saw the light of day until after her death in 2009. When John Maloof, a young scholar but veteran storage unit auction scrounger ran across a trunk of her negatives, he didn’t know what to make of it.

But he recognized her sharp eye, Maier’s gift for holding her camera waist-high and snapping arresting street scenes, portraits and garbage can still-lifes. When he couldn’t interest the major photography museums in this unknown, he started posting them online. People noticed.

And when he started digging into who this person was — she was a nanny, and a hoarder who kept everything from clothes and newspaper articles to receipts — her arresting back story and compelling images became an art photography phenomenon.

Chances are, you’re familiar with this much about Vivian, who died in 2009. Newspapers, magazines and TV news feature stories celebrated her work even as they rarely got past the surface of her life.

1954, New York, NY

Maloof and filmmaker Charlie Siskel’s “Finding Vivian Maier” is the more complete account, a moving and troubling investigation into someone who died obscure but who lives on thanks to the work she dedicated herself to.

Maloof tracked down the children — now adults — raised by her. Some of her many employers — the talk-show host Phil Donahue was one — are still living, and were willing to ponder this mystery who once lived under their roof.

He found expert photographers to wax on about her talent and speculate on the personality revealed in her shots. He dug up her family history, and into her travels.

And he developed film and plays back cassettes, showing the woman as she presented herself to the world, a deep and flutish voice with an obscure European accent. She sounded like Isabella Rossellini. Talk, with a De Gaulle nose, she looked French, which is the way she introduced herself.

But the truth is far stranger. And Maloof and Siskel reveal it only gradually. They structure their documentary thusly — negatives found, fame and acclaim follow, a post-mortem triumph. And then the REAL Vivian starts to emerge.

The Oscar-nominated “Finding Vivian Maier” may follow the standard “find a killer subject and the world’s your oyster” documentary recipe. But it breaks the formula for such eccentric biographies, and leaves as many mysteries as it solves. Staring into those photos, we and she would have it no other way.

MPAA Rating: unrated, with adult themes

Cast: Vivian  Maier, John Maloof, Bindy Bitterman, Virginia Kennedy, Phil Donahue
Credits: Directed by John Maloof and Charlie Siskel A Sundance Selects release.

Running time: 1:23