Thousands of photos viewed, hundreds of interviews, 12 years of work: Arthur Lubow’s 612-page biography of fine art photographer Diane Arbus represents a special kind of love.

“One of the people I interviewed, [Arbus subject] Marilyn Nielsen—we were having a drink in a hotel on 60th Street and after about 20 minutes she said, ‘You’re in love with her, aren’t you?’ ” Lubow laughs.

“It’s not quite true,” he says, “but—this woman had just been photographed by her, so she didn’t know her at all; she knew her as a somewhat dirty and unkempt person at a black-tie ball—for me, yes, I’m just endlessly fascinated by her. So I guess that can be defined as a form of love.”

Lubow, who lives in Connecticut, is an award-winning journalist whose decades-long career includes turns as a New Yorker staff writer and Vanity Fair contributing editor. He fell for Arbus while working on a 2003 cover story for The New York Times Magazine, “Arbus Reconsidered,” and came to know her as a wholly original—and woefully under-appreciated—American artist.

“I think too many people think of Diane Arbus as a photographer of freaks, transvestites, other marginal figures,” he says, “when in fact that was only a small part of her subject matter, and there are other lesser photographers who do that sort of thing. Really, she was somebody who’d be better discussed in the company of writers like Kakfa.”

Diane Arbus: Portrait of a Photographer—a seductive, devastating, and definitive biography—makes a passionate case for reconsidering Arbus thus. Born Diane (pronounced “DEE-an”) Nemerov on March 14, 1923, to a family of successful Manhattan retailers, she made an early marriage to a promising art department employee at the family store. Allan Arbus’ subsequent foray into fashion photography cast his young wife in the role of set dresser and designer, which she despised.

“ ‘I hate fashion photography because the clothes don’t belong to the people who are wearing them,’ she said. ‘When the clothes do belong to the person wearing them, they take on a person’s flaws and characteristics, and are wonderful,’ ” Lubow writes.

She soon eschewed the artifice of advertising for the truth of art.

“It wasn’t just truth she was after, but Truth,” he writes. “She wanted her pictures to reveal profound verities, to pry out what was invisible to the casual eye.... She spent weeks, and sometimes years, getting to know her subjects so well that they dropped their guard in her presence.”

“ ‘I love secrets, and I can find out anything,’ ” he quotes Arbus saying.

Arbus left her husband’s business and, ultimately, the marriage, though the two remained enmeshed throughout her life. She raised their daughters, Doon and Amy, while building a business as a freelance magazine photographer, which supplemented sessions with subjects of her own choosing. They included dwarves, transvestites, giants, and nudists, yes—but also families, children, couples, twins. (Among the most famous is “Identical Twins, Roselle, New Jersey 1967,” an inspiration for Stanley Kubrick’s The Shining.)

“Diane defined herself by the way she was seen and, conversely, by what she saw,” Lubow writes. “The photographs that a decade later would establish her reputation seemed new because they recorded the intensity of that reciprocal locked-eye vision: Arbus scrutinizing her subjects, and those subjects illuminating her with their gaze.”

In her time, Arbus faced a fair share of scrutiny: the art world was still relatively inhospitable to photographers—recognition of the medium as art is a change Arbus helped bring about, Lubow argues—and it was terribly hard, at times, to make money. Moreover, she was accused of exploiting her subjects by critics including Susan Sontag.

“The original, wrong-minded criticism of which Sontag is the most influential exponent, is that these are all truly exploitative, mocking pictures,” Lubow says. “Then the counterargument, by Doon [the daughter who manages Arbus’s estate] and others, was no, in fact that she had some sympathy for these people and identified with them.

“I think there are elements of both,” he says. “There is a certain kind of cruelty but there’s also an empathy and you don’t know where she stands, precisely, which means you don’t know where you stand, and that’s what makes people so uncomfortable, what gives them their skill, their power. They’re very hard to pin down.”

Sadly, her career would be a short one: Arbus, who battled depression, died by suicide on July 21, 1971. She was at the height of her powers, says Lubow, who hopes that readers will come to appreciate his subject for her humanity as well as her artistry.

“She was always trying to reinvent herself,” he says. “She had this almost morbid fear of repeating herself, of being copied, so she was reinventing herself up to her death, which is part of what’s so poignant about it. There’s no one else like her, really, and it’s an amazing accomplishment.”

Megan Labrise writes “Field Notes” and features for Kirkus Reviews.