New York Post: "The prose is spare, emotionally resonant — and completely addictive.”

If you thought J.D. Salinger and Harper Lee were reclusive, you obviously haven’t met Elena Ferrante — then again, no one really has. The Italian author of the Neapolitan novels, who has garnered a worldwide cult following, writes using a pseudonym — and it’s one of the best-kept secrets in book publishing.

It’s said that only her publisher and a few close acquaintances know who she really is.

This month, “The Story of the Lost Child,” the fourth and final installment of the decades-long saga that began with “My Brilliant Friend” (published in Italy in 2011), appears in English — and thus the literary frenzy reignites. The series, which tells the story of the complicated lifelong friendship between working-class Neapolitan girls Elena Greco and Lila Cerullo, has become a word-of-mouth sensation, selling more than 1 million copies and appearing in 27 languages.

In an industry where authors must tweet, Instagram, appear in promotional videos and generally act as carnival barkers for their written wares, the idea of a writer who does nothing but write is fantastically mysterious.

“I’ve already done enough for this long story: I’ve written it,” she wrote in a 1991 letter to her editor when her first novel, “Troubling Love,” was released. “If the book is worth something, it should be enough. I will not participate in debates and conferences, if I am invited. I will not go to accept prizes, if I am given any. I will never promote the book, above all on television, in Italy or, should the need arise, abroad. I will only participate through writing, but I will also try to keep this to the bare minimum.”

Of her need for anonymity, she recently told Vanity Fair that “I simply decided once and for all . . . to liberate myself from the anxiety of notoriety and the urge to be a part of that circle of successful people, those who believe they have won who-knows-what.”

And if that weren’t clear enough, she has threatened to stop writing altogether if her identity is ever uncovered.

Left to do nothing but read her books and speculate wildly, fans have even come up with a Twitter hashtag: #FerranteFever (“can you sign the book to me? Since no one knows who the author is?” tweeted one reader).

Ferrante’s publisher, Europa Editions, held midnight book-release parties in Brooklyn, Manhattan, Los Angeles and Houston (sans author, of course) to celebrate the English translation by Ann Goldstein. She has many fans among her fellow authors, among them Zadie Smith, Jhumpa Lahiri and Claire Messud.

Not many series can sustain a reader’s interest across six decades and 1,700 pages of often slow-moving narrative, but Ferrante pulls it off. The prose is spare, emotionally resonant — and completely addictive.

Her depiction of the inner lives of the two women — and the tense, often tortured friendship they share through changing ambitions, men, money, children, school and work — is spot-on, making the rumors that Elena Ferrante is really a man seem all the more ludicrous.

And yet speculation has continued, with some in Italy convinced that the real “Ferrante” is Neapolitan author Domenico Starnone, who disavows the rumors completely. “Let’s say I am Ferrante, or that my wife is,” he told the Guardian (it’s also been suggested that his wife is Ferrante).

“Explain to me one thing: Given that it is so rare, in this mud puddle that is Italy, to have international reach, why would we not make the most of it? What would induce us to remain in the shadow?”

Fair point. Most authors know they have to make the most of any publicity they get. But for now, Ferrante’s secret is safe — and her books hold up, hype or no hype.