Mary McCarthy would have turned 90 on June 21, a fact that is itself astonishing to those who remember her flagrant youth, when her sharp style made her the most feared and forthright writer in New York. Her birthday was marked by a symposium at CUNY's Center for the Humanities and, soon afterward, the publication of an excellent new selection of her essays, A Bolt From the Blue and Other Essays (New York Review Books, $24.95), edited, with a penetrating introduction, by A.O. Scott.

McCarthy was born in Seattle in 1912, lost both her parents to the flu epidemic six years later and, after graduating from Vassar in 1933, began publishing witty, acid, even wrongheaded reviews in The Nation and The New Republic. (In one review, for example, she missed the strength of Steinbeck's In Dubious Battle, easily one of his best books, out of sheer dislike for proletarian realism.) In 1937 she helped revive Partisan Review as an anti-Stalinist journal and became its theater critic, but soon, with the publication of The Company She Keeps in 1942, she found herself more celebrated for her fiction than for her critical writing, a balance that would shift by the late 1960s. She reigned for decades as one of America's most brilliant intellectuals, until she died of cancer in 1989.

I didn't really know Mary McCarthy, though I visited her on two memorable occasions when I was teaching in Paris in 1981. But from the early 1960s I knew her work intimately, and I was enthralled by its rare combination of abrasive intelligence and sexual bravado. I thought of her as not one but many writers–the endlessly self-questioning independent woman of her best book, The Company She Keeps; the keenly observant satirist of The Oasis, The Groves of Academe and The Group, with a highly developed sense of the ridiculous; the autobiographer who re-created her abused and orphaned childhood in Memories of a Catholic Girlhood; the richly cultivated traveler of her books on Florence and Venice; and the prose stylist of dazzling clarity in many literary and personal essays, written with a scalpel as much as a pen.

Thanks in part to the weakness of her last novels, the consensus seems to have hardened that in her fiction McCarthy somehow failed to impose herself, and that she will be remembered primarily as an essayist. Despite her formidable gifts as a polemical and discursive writer, this makes very little sense. First, for all her reputation as an intellectual who sacrificed feeling to intelligence, what powers McCarthy's best essays, by and large, are her fictional rather than strictly intellectual gifts. Again and again she makes her points by telling stories, or by way of vivid description, arresting images, subtle characterization. Unlike many of her Partisan Review contemporaries, there are no special ideas we associate with her name. As a thinker she was the perpetually bright-eyed student, enormously impressive without really leaving a mark. "A Bolt From the Blue," her ingenious dissection of Nabokov's Pale Fire, may be the best term paper ever written, a marvel of ingenuity but not much more. Realistically, she made only modest claims for her theater criticism, and was quite amusing about how she fell into it. (Her first husband was an actor and playwright, she tells us, and the "boys" at PR didn't take theater very seriously.)

No critic of her period who hated Odets and the Group Theatre, who wrote about A Streetcar Named Desire without mentioning Marlon Brando, who wrote about the operatic version of Street Scene without mentioning the composer, Kurt Weill, who dismissed The Iceman Cometh simply as bad writing is likely to go down in history for any special feeling for the theater. Instead her essays give ample evidence of highbrow condescension toward the theater. Other essays, like "America the Beautiful," are saved by wonderful writing, though they are hemmed in by the intellectual prejudices of the moment, laced with a touch of snobbery all her own. In that essay she is astonished that the visiting existentialist Simone de Beauvoir would ever want to eat at a "real" American restaurant, or take in a play, or see an American movie, or have a peek at Congress in session, with its "illiterate hacks whose fancy vests are spotted with gravy, and whose speeches, hypocritical, unctuous, and slovenly, are spotted also with the gravy of political patronage." This sin of attitudinizing is compounded when she takes precisely the opposite tack a few years later in reviewing de Beauvoir's book, which had degenerated into an obtuse anti-American tract. She accuses her French counterpart not only of being careless of facts, unobservant–a cardinal sin, in McCarthy's book–but of a reflexive condescension not so different from McCarthy's earlier viewpoint. In the interim, many of New York's alienated intellectuals had come home.

McCarthy's essays are strongest where they overlap with her fiction and memoirs. Her obituary pieces on Philip Rahv, Fred Dupee and Nicola Chiaromonte are striking character sketches that emerge from a well of deep feeling. One of her finest essays, "Artists in Uniform," about her awkward encounter with an anti-Semitic Army colonel, is virtually indistinguishable from a short story; in fact, Harper's first published it as a story, as if to remove the bite of actuality from it. Later she wrote another piece for Harper's ("Settling the Colonel's Hash") reflecting on the differences between an essay and a story; in her case, she recognized, the line was hard to draw. (Neither of those essays is included in A Bolt From the Blue but can be found in her superb 1961 collection On the Contrary, which gives us McCarthy at the height of her powers as an essayist.)

For all her exacting sense of fact, one of McCarthy's ultimate contributions was to blur the distinctions between different kinds of prose writing, to show how fiction could be opened up to the thinking mind and how essays could profit from the techniques of fiction. Her first novel was a loose collection of linked stories. Because she was imbued with the Catholic practice of self-scrutiny, her fiction could grow as analytic and introspective as her essays. As A.O. Scott writes of the heroine of that first book, Meg Sargent, she "marries and divorces, goes to dinner parties, editorial meetings, and her analyst's office, has affairs with pedigreed intellectuals and traveling salesmen, but mainly what she does…is think, argue, criticize." Only the novelist in McCarthy could give her critical mind its rich texture and immediacy.

Several chapters of Memories of a Catholic Girlhood had already appeared in a collection of stories, Cast a Cold Eye. Once integrated into the memoir, they were followed by second thoughts and factual corrections. Another of her best essays, "My Confession," is really a reflective memoir that describes both her haphazard political education and the progressive culture of the 1930s, built around the peculiar mores of the Communist Party. How shall we take these pieces? As she says of "Artists in Uniform," "I myself would not know quite what to call it; it was a piece of reporting or a fragment of autobiography." In her own way, she was a pioneer of the hybrid New Journalism of the following decade. Along with another fiction writer, James Baldwin, she created the serious personal essay of the postwar years.

A page later she adds a trenchant observation that offers a clue as to why we should not slight her fiction in celebrating her essays. One of the qualities that "Artists in Uniform" and "My Confession" share with her early fiction is a sense of the woman herself not as prepossessing, in control, but as tentative, ambivalent, even at moments cowardly and ashamed. She looks back on her own confusions with unfeigned regret. A schoolteacher had written to congratulate her on her so-called story in Harper's: "We thought it amazing that an author could succeed in making readers dislike the author–for a purpose, of course!" This benighted response must have heightened McCarthy's awareness of what she had actually done. "I wanted to embarrass myself," she says, "and, if possible, the reader too." In the original essay this proved to be a good strategy for exposing genteel anti-Semitism, along with the awkwardness or complicity of engaging with it; but it was also much more, perhaps a key to McCarthy's work at its best. Her writing was strongest when she was as hard on herself as she could be on others.

We can readily recognize this embarrassment from the predicament of Meg Sargent in "The Man in the Brooks Brothers Shirt," when she finds herself in an unthinkable sexual encounter on a train, or in "Ghostly Father, I Confess," where she is caught in an impossible marriage to a man very much like Edmund Wilson. Her social embarrassment is always linked to the state of her soul. McCarthy's rueful feelings about her own behavior run through "The Weeds," a story based on her attempts to leave Wilson, and through some of the Dickensian early chapters of Memories of a Catholic Girlhood. The common denominator in all these texts, whether comic or horrific, whether they focus on the safety pin in the underwear or the protracted nervous breakdown, is the protagonist's sense of vulnerability–the woman with her guard down. This is something McCarthy habitually leaves out of her satiric or critical writing, where a more self-assured, more destructive, though also more witty side of her personality comes into play. Unfortunately, this tart-tongued double is the only McCarthy some readers remember, though it's not necessarily the woman her friends recall or the writing they most value. One of her biographers, Carol Brightman, may exaggerate when she refers to her "nearly inexhaustible appetite for remorse and self-castigation," but this undoubtedly brings us closer to the welter of emotions behind the icy sheen of her brisk intelligence, her famously "cold eye."