Nobody hopped up on a pedestal like the writer Mary McCarthy. In the ’30s, she came out of nowhere, across the Continental Divide from Seattle to Vassar to Manhattan, a hyperliterate orphan with a fresh mouth and vast superiority complex who had drunk the blood of the Sacred Heart and Cicero and was thirsting for attention. The emotional chill and routine abuse of her famous Catholic girlhood had endowed her with lethal reflexes by the time she launched her career in 1935, at age 23, with a serial attack on the literary establishment in the Nation titled “Our Critics, Right or Wrong,” from which came this sentence, like a clarion: “It was not the man in the street who, unable clearly to express his delight in [Thornton Wilder’s] ‘The Woman of Andros,’ cried aloud that it reminded him of Theocritus; it was Dr. Henry Seidel Canby of Yale University.”

And that was, as they say, only the beginning. She would effectively finish her career—you might say her career would finish her—in a 1980 appearance on The Dick Cavett Show, when she remarked of writer Lillian Hellman that “every word she writes is a lie, including ‘and’ and ‘the.’” McCarthy was essentially if not technically right about Hellman, but Hellman tried to spin one last lie by suing McCarthy for $2.25 million. The plaintiff, however, died in 1984, before the suit concluded, disappointing the defendant terribly. “There is no satisfaction in having an enemy die,” McCarthy said.

In the intervening decades, telling everyone everything she thought she knew in places like the Nation, the New Republic, and Partisan Review, McCarthy often found herself all cold and naked up on her high horse. She believed herself so politically transcendent that she once claimed to have found a third way—pity—around Hitler. But she wound up royally pissing off Hannah Arendt, the Jewish refugee philosopher who, after a patching over, eventually became her intellectual mama. (Big irony of her life: Years later, McCarthy wound up defending Arendt’s pity for Nazi war criminal Adolf Eichmann against a hopping-mad group of Jewish intellectuals.)

During the Vietnam era, McCarthy, the New York intellectual who had refashioned herself as a Paris expat intellectual, thought she could summon the power of Calliope and literally end the war by covering it for the New York Review of Books. But the episode turned into Gidget Goes to Hanoi: She only managed to appall her colleagues—especially those of the penised type, and especially the Vietnam writer David Halberstam—by accepting flowers from North Vietnamese Prime Minister Pham Van Dong, among even graver reportorial faux pas.

“Oh poor girl, really,” the clear-eyed poet Elizabeth Bishop, Vassar ’34, wrote in 1954 of the cold-eyed literary siren McCarthy, Vassar ’33. “You know, I think she’s never felt very real, and that’s been her trouble….[I]n those days her pretensions were so romantic and sad. Now that they’re so grandiose, I suppose it’s much harder to take.”

“She was always taking the high road,” said her Partisan Review colleague William Phillips. “It could be annoying.”

Pretentious, pompous, often insufferable—but we already knew that about McCarthy because two large forests had already been cut down to publish biographies of her: Carol Gelderman’s Mary McCarthy: A Life and Carol Brightman’s Writing Dangerously: Mary McCarthy and Her World. The first impulse is to bash author Frances Kiernan with a rough board for thinking she needed to level a third to put together Seeing Mary Plain: A Life of Mary McCarthy, particularly because so much of her material consists of quotes and anecdotes recycled from previous bios.

Seeing Mary Plain builds a lively conversation, though, on reams of oral history from folks who do take satisfaction in seeing an enemy die (check the index for Diana Trilling, toward the back), alongside bits of letters, articles, court documents, you name it. Lively, that is, when Kiernan, a former New Yorker fiction editor, sits back and stays out of it, for the book’s least sparkling writing is the author’s own, cheap and perfunctory: If you hear an awful sentence in “That there was pathos and even tragedy in the children’s situation was not lost on her,” or “That there was loyalty and affection there was no question,” try: “That this battery of questions was brought forth with some intention of currying favor with the recipient of the letter is quite possible.”

But Kiernan’s great accomplishment is to assort the known material amid a sheaf of new stuff and sharply recast the lioness as a fox: Mary McCarthy, indomitable voice of political conscience, becomes Mary McCarthy, highly clever moral poseur. Highly clever. Merely clever.

“If only she were less clever, or more,” said her longtime friend Dwight Macdonald.

“[O]ne of the cleverest women around,” noted Delmore Schwartz. And “half a fool.”

Nobody who loved Mary McCarthy didn’t hate her at some point, too, and there were plenty of others who just plain hated her straight through. Kiernan gets her winnings from a kind of dirty pool, in that this biography is the first one started and finished posthumously, well out of McCarthy’s range of rejoinder. With its abundance of cigarettes, sauce, and scandal—the fully employed sexuality, the four marriages, the nervous breakdowns, The Group—the book forms a postage-stamp quilt of a portrait, at the center of which shines the thing people feared most about McCarthy: “that smile.” That radioactive rictus, bright and deadly like the sun. “She could do many things with that smile,” recalls one observer. ‘Even smile with it.”

Whether they regarded her as a prodigy, polymath, quick study, or dilettante, most witnesses would concede that McCarthy was a consummate stylist in all events. She amazed herself, and quite often those nearby, with her literary promiscuity: a tellingly randy first novel, The Company She Keeps; followed by a haunting, hilarious memoir, Memories of a Catholic Girlhood; followed, variously, by theater criticism; a few minutes spent imploding John Hersey’s Hiroshima; the high-IQ travelogues Venice Observed and The Stones of Florence; fabulous essays on Flaubert, Nabokov, and Burroughs; a Watergate folly; and a couple of new novels in the ’70s, as distraction drove her writing career into the ground and we might as well have been reading Brooke Astor.

As often as McCarthy dazzled the crowd, she shocked it with her hubris. The bites into McCarthy come so fast and hard in Seeing Mary Plain that it reads as if a bunch of literary ants were picnicking on the remains of a big dead spider in a memorial act of revenge. Accordingly, her presumed status as the bellest of lettrists moves into the margins.

“Her Italian was atrocious,” snorts Eleanor Clark, Vassar ’34 and later the wife of Robert Penn Warren. “She didn’t know a goddamn thing about Italian history, Italian art, Italian anything.” Dwight Macdonald’s wife, Gloria Macdonald, recalls that “We’d stand in front of a painting and she’d give us the whole background history—sort of like a tone-deaf person listening to music.”

As she grew older and crankier, McCarthy could hear the tenor of her times no better. She became a willful Luddite crusading with an uptown attitude, a conscientious objector to lies, as always, but also to the dumbest things—credit cards, Cuisinarts. McCarthy was, as she once described the Ladies of the Sacred Heart, “like all truly intellectual women,” a romantic desperado. The half of her that was a fool—the half that “lived in vain,” as she suggested late in her life—developed enormous blind spots in her vision of humanity, selectively ruling by an ever-failed set of Voltairean beliefs that rendered her increasingly remote from a world she saw forever in crisis. CP