One of the melancholy facts of a critic’s lot is that however much clout we might wield during our lifetimes, few forms of writing date as quickly or slide so readily into obscurity. The rare critic who crosses over to become a creator of the form he once wrote about—the filmmakers François Truffaut and Peter Bogdanovich are the most familiar examples—will soon see the later work eclipse the earlier. That Susan Sontag was primarily a critic wasn’t a controversial thing to observe during her life, although you didn’t want to do that within her earshot. Benjamin Moser’s new biography of the writer, Sontag, recounts a furious diatribe she delivered from a podium at Skidmore College in 1996, directed at the old friend who had introduced her. “He still doesn’t get that I’m a novelist and that all this other writing he talked about is writing I did to keep writing and have something to do while I was developing myself as a fiction writer,” she told the crowd.

Nevertheless, it is the essays, not the handful of novels she wrote (the most successful of which was 1992’s The Volcano Lover), for which Sontag will be remembered. Or will she? Trying to explain why I was reading an 800-page biography of this woman to a friend who had never heard of her, I soon ran aground. What makes Sontag an important figure, a woman who, as Moser puts it, “for almost 50 years … more than any other prominent public thinker, had set the terms of the cultural debate in a way that no intellectual had done before, or has done since”? In the first place, this statement is patently untrue. Samuel Johnson, John Ruskin, and Denis Diderot are just three critic-intellectuals easily as influential and renowned in their own times.

Partly because, as Moser illustrates, Sontag was forever qualifying and contradicting herself, it’s also strangely difficult to come up with the important idea or argument that Sontag formulated, the key to understanding the culture for which she will forever be known.

Hannah Arendt, for example, decimated the archetype of grandiose, Byronic villainy by identifying the “banality of evil” in Adolf Eichmann. Marshall McLuhan’s concept of the medium as the message remains a powerful tool for thinking about new technologies. Once you’ve read Leslie Fiedler’s “Come Back to the Raft Ag’in, Huck Honey!” it’s impossible to ignore the recurring motif of quasi-homoerotic racial pardon in so much American fiction. Pauline Kael celebrated American popular film as worthy of sustained critical attention, and developed a style and approach so distinctive that its influence can be easily spotted in the generation of critics that followed her and today. I know a Kaelian argument when I see it, but what is the Sontagian mode? What species of analysis is recognizably hers?

One thing’s for certain: Whatever it is, it is serious. “Serious” is a word that recurs over and over in Sontag, emanating most often from the book’s subject. In 1963, Sontag called for the novel to become “what it is not, in England and America with rare and unrelated exceptions: a form of art which people with serious and sophisticated taste in the other arts can take seriously.” Identifying and expounding upon that sort of art was the supremely serious practice. “The wisdom that becomes available over a deep, lifelong engagement with the aesthetic,” Moser quotes Sontag writing late in her life, “cannot be duplicated by any other kind of seriousness.” A character in a Sontag short story published in the 1978 collection I, etcetera is called “the slave of seriousness.”

Confusing the matter is that Sontag’s debut as a critic of consequence—the essay “Notes on ‘Camp,’ ” which appeared in the Partisan Review in 1964—was received by the old guard of New York’s intelligentsia as a blow against seriousness. She was a young woman from the provinces: the child of a self-made fur importer, who died in China when Sontag was 5, and a vain, manipulative, alcoholic mother whose baleful influence Sontag believed to have blighted her own chances for romantic happiness. As a girl, growing up in Arizona and California, she sought comfort in books. A high school classmate recalled her as “so focused—even austere, if you can call a fifteen-year-old austere.”

She could be moved to tears by classical music (with a similarly inclined friend she debated how many additional years of Stravinsky’s life they’d be willing to buy with their own extermination), and her favorite author was Thomas Mann. Educated at the University of Chicago, she passed through an eight-year marriage to an academic, Philip Rieff, who fathered her only child: a son, David. (Moser makes a case that it was Sontag who wrote all or most of Rieff’s best-known book, 1959’s Freud: The Mind of the Moralist.) Then she arrived in Manhattan, with no greater dream than “to write for Partisan Review and be read by 5,000 people.” None of that makes her sound like a barbarian at the gates.

Sometimes the attitudes of the relatively recent past are harder to explain than the way people thought centuries ago; we assume that values couldn’t have changed that much over a handful of decades. Moser has the unenviable task of correcting this illusion. In addition to its more infamous prejudices, he writes, “American society was riven by other taboos that, though almost entirely forgotten now, make it hard to understand how a person as intimidatingly erudite, as polymathically allusive, as Susan Sontag could have been attacked as a mongrelizer, a leveling popularizer whose prominence was a sign of decadence.” The very idea that someone would write seriously about gay counterculture (and in the Partisan Review, the epicenter of the group known as the New York Intellectuals, no less!) or, as Sontag did in one instance, liken her response to Robert Rauschenberg’s paintings to the feeling imparted by “a song by the Supremes,” threatened the ostensibly unbreachable wall between highbrow and lowbrow culture. As Moser puts it, the New York Intellectuals saw a critic’s proper role as “forming a prophylactic shield against the pollution tainting everything they held dear. The culture they defended was the culture that despised and rejected anything too easy, too popular, too in thrall to money and image and success.”

This battle, as you’ve surely noticed, was lost a while back, but as Moser goes on to point out, “to read Against Interpretation, Sontag’s first book of essays, where ‘Notes on “Camp” ’ was published in book form in 1966, is to ask: If this woman is an enemy of high culture, who could possibly be its friend?” She had not abandoned her adolescent austerity, and a few references to pop songs or an interest in the elaborate ironies in gay men’s engagement with mainstream culture did not signal the collapse of her daunting criteria. She remained, to the end of her days, a slave to seriousness, advocating for plotless and punishingly obscure European novels, directing movies with three-minute-long scenes of pigeons pecking around, scolding other artists for their moral failings.

Along the way, she wrote stylish essays that, most notably, argued that photography threatened to collapse real events and people into interchangeable commodities and condemned then-common assertions that illnesses like cancer had psychological or moral causes. These are sound points, but hardly revelatory. Beautiful and charismatic, she slept with both men and women—her lovers included Robert F. Kennedy; Warren Beatty; an Italian duchess who, according to Moser’s sources, did “absolutely nothing” and had never read a book; and the photographer Annie Leibovitz, who was her partner for over a decade until Sontag’s death from leukemia in 2004. A square in the Bosnian city of Sarajevo is named after her, honoring her activism while the city was under siege in the early ’90s. She staged a candle-lit performance of Samuel Beckett’s Waiting for Godot there in 1993, drawing international attention to the crisis.

According to Moser, Sontag was not “especially interested sexually” in men; her great passions were all women, and all were affected by her conviction that “relationships are essentially masochistic.” She bullied some partners (her treatment of Leibovitz shocked even her close friends)—and, according to many of Moser’s sources, was bullied by others, fully prepared to grovel and otherwise abase herself before her beloved. Her relationship with her son was at once clinging, controlling, and oddly cold. According to the writer Jamaica Kincaid, who befriended David, “She really wanted to be a great mother, but it was sort of like wanting to be a great actress, or something. … She had no real instinct for it. I would say there was no real instinct for caring about another person unless they were in a book.” And yet this was not entirely alienating. “It was just Susan-ness,” Kincaid told Moser. “None of the words or the ways of characterizing her behavior really fit. … She was just a great person. I don’t think I ever wanted to be a great person after I knew Susan.”

It was this ineffable stature that made Sontag significant—as tautological as that may sound. She personified an idea of American intellectualism that was fully equal to the intimidating thinkers of France and Germany. Her journals, published after her death, revealed her to be riven with insecurity and feelings of inauthenticity. Moser believes this is because she was closeted, her lesbianism the sort of “open secret” people in her own social circle knew about and were unfazed by, but that went unmentioned publicly. (He also attributes many of her problems to her mother’s alcoholism.) Averse to writing about herself, she famously completed Illness as Metaphor without a single mention of her own battle with cancer. “Throughout her life,” Moser writes, “the more personal the issue, the more energetically she strove to recast it intellectually.”

Rather than rerouting the intellectual currents of her time, Sontag rode them. She was a gifted writer, but the creation that made her famous was Susan Sontag, iconic enough to appear in Woody Allen films and Absolut Vodka ads as Herself, the embodiment of a fantasy about the modernist, urban life of the mind. Perhaps her lesbianism, if acknowledged, would have undermined that, as Moser insists, but perhaps not. Nevertheless it, and everything personal and vulnerable about her, was also superfluous to that image, except for the fact that (after the early fiasco with Rieff) her sexual orientation kept her from marrying, and therefore appearing subordinate to, a male intellectual. She had no interest in featuring her identity—as a woman, as a lesbian, or even as a Jew (she took her stepfather’s name, abandoning her surname of birth, Rosenblatt)—as a central feature of her persona, as the famous often do today. She seems to have resisted this in favor of becoming a more “universal” writer/symbol, although that hasn’t prevented brainy young woman from adopting her as a role model.

Celebrity is a two-way exchange. The famous—and Sontag admitted to a friend that “I have done everything I have to do to become famous”—provide their public with a focus for a mass of inchoate needs and desires arising in a particular historical moment. The Western world, for a few decades in the last half of the 20th century, wanted a Susan Sontag, a figure who reassured everyone that the ascendant superpower would respect and abide by and even equal the thinking of the Old World. In return for fulfilling such roles, the famous enjoy benefits that may or may not be material: Sontag didn’t make much money from her writing, but she had many admirers and patrons, including her longtime publisher, Roger Straus, and, eventually Leibovitz, to keep her in comfortable circumstances. And she was human enough to thrill at being recognized by newsstand operators and strangers at airports.

It should not be surprising, though, that someone as smart as Sontag also found her fame unsettling. Moser writes that “one of her great themes” was “the distance between the shadow-world of images and the wartier reality of life.” This seems a paradox, but no more so than the title and premise of one of her most famous essays, “Against Interpretation,” considering that she spent her life championing art that most people had to have explained to them by a critic like herself. Or that she resolved that what the besieged of Sarajevo, hungry and dying at the rate of 10 per day, really needed to see was a Samuel Beckett play. On her own deathbed, she wanted only Hollywood musicals, Fred Astaire, and Cary Grant.

And of course seriousness itself let Sontag down. In 1996, looking back over her career, she wrote:

What I didn’t understand (I was surely not the right person to understand this) was that seriousness itself was in the early stages of losing credibility in the culture at large, and that some of the more transgressive art I was enjoying would reinforce frivolous, merely consumerist transgressions. Thirty years later, the undermining of standards of seriousness is almost complete, with the ascendancy of a culture whose most intelligible, persuasive values are drawn from the entertainment industries. Now, the very idea of the serious (and the honorable) seems quaint, “unrealistic,” to most people.

Fifteen years after her death, it is so difficult to explain why Sontag mattered because it had less to do with what she said and wrote than with how she was in the world, or with how she appeared to be. She was just what we needed—or at least what we wanted—at the moment, and the moment has passed.

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