October 16, 2013 4:01 AM EDT

Diane Arbus said, “A photograph is a secret about a secret. The more it tells you, the less you know.” The odyssey of Vivian Maier is proving to be further proof of this. Discovered accidentally in 2007 by Chicago historian and collector John Maloof, the street work of the as-yet unknown nanny rippled quickly through the world of photography. Maier’s talent and the clarity of her vision drew instant admiration. The number of photographs she had taken (more than 150,000 negatives have been found) and then meticulously hidden from all those who had known her endowed her with a near mythical status. The forthcoming book, Vivian Maier: Self-Portraits, to be released this October 29 by powerHouse, concurrent with the release of the documentary film, Finding Vivian Maier, directed by Mr. Maloof and Charlie Siskel, would seem to offer answers to the many questions surrounding Ms. Maier’s legacy. On the contrary, however, it seems that the deeper one delves into her life, the more enigmatic and mysterious she becomes.

Below, Mr. Maloof and Elizabeth Avedon, who has provided the introduction to Self Portraits, discuss Vivian, her work, and what they have gleaned about the prolific and ever evasive artist.

Elizabeth Avedon: As you reconstructed her story through your film and upcoming book, what is most important about Vivian Maier’s work for you?

John Maloof: One of the things that fascinated me early on was the fact that Maier was shooting photos prolifically while she had a career as a nanny and, at the same time, didn’t show her work to anyone for feedback. So, to me, this is the mark of a true artist; someone who can create a large body of work by themselves as an expression of their true self and it speaks to all of us in our own way. That’s important. She didn’t try to become famous, she didn’t create images for others and she didn’t see things that she knew others would appreciate. She saw the world in a personal, uninfluenced way, and her photos are a raw depiction of that world she saw. The photos are beautiful and important because, not only are they great images, they are not contrived.

(Related: For a look at self-portraiture in the digital age, see today’s LightBox feature on the National #Selfie Portrait Gallery in London.)

EA: Viewing Maier’s place in the cannon of self-portraiture alongside the likes of Cindy Sherman and Lee Friedlander, what contribution do you believe was her most essential to that genre?

JM: The fact that Maier is a woman and also using the square format may have helped distinguish her. But I feel that perhaps the main contribution to that genre is that she used photography (which wasn’t really considered art in her time) to express herself artistically. Many photographers had jobs at major agencies such as Magnum or Life and they would create on their own among peers such as the Photo League and there was definitely a feedback loop that influenced many of them to go a certain way with their work. Maier went her own way, the only way she knew, which was to express herself through photography. And I think this is essential because to have photos that are as classical as hers, and to not have been trained, is a rarity in that time.

EA: There is one particular image of Maier casting a full-length reflection in a window, two women sitting together fall within her shadow. It’s a wonderful layered image. What are your thoughts on this photograph and Maier’s frequent use of her own reflections and shadows?

JM: It seems that Maier was an outsider looking into the lives of others. People weren’t aware of how great she was as an artist but she didn’t need that validation to keep going as a photographer. She could see a moment that was more unobtrusive and intimate yet powerful. As a frugal person, she knew she had to strive to get the shot perfect to not waste film. The women’s legs match up with Maier’s, she’s looking in from the outside at a mother and daughter (presumably), the glow from the light behind the plant inside illuminates Maier’s camera, and there’s a perfect break in the background where there are no buildings or trees blocking the sky so her silhouette can be in the composition. It’s perfect.

( See more: Vivian Maier: The Secret Shutterbug )

Vivian Maier: Self-Portraits, edited by John Maloof, is available through powerHouse Books.

Elizabeth Avedon is an independent curator and writer. Follow her on Twitter @elizabethavedon.

John Maloof is a filmmaker and street photographer who lives in Chicago. Follow him on Twitter @johnmaloof.

Mia Tramz is an Associate Photo Editor at TIME.com. Follow her on Twitter @miatramz.

More Must-Read Stories From TIME

Write to Mia Tramz at mia.tramz@time.com.

You May Also Like