The Boston Globe

Lorenza Moronetti was so captivated when she read “My Brilliant Friend,” the first book in the quartet, that she had to talk to someone, anyone, about the striking tale. She started a Ferrante book club, which meets every other Saturday at I AM Books in the North End.

“All of the characters are very real and very passionate,’’ says Moronetti, a biologist who started the saga at the suggestion of a friend in her native Milan. “Every time you finish a book, you cannot avoid the next one. You cannot stop reading.”

Ann Marie Lipinski, curator of the Nieman Foundation for Journalism at Harvard University, also found herself swept away. “During the intoxicating reading period, I resented anything that intruded on my time with the books,” she says in an e-mail. “And every time I went to the bookstore to purchase the next volume, I would buy them for a friend I thought should read them, too.”

This comes as no surprise to Nicola Orichuia, co-owner of I AM Books, who says novel sales are brisk, and nine out of 10 buyers are women.

Brisk indeed. Without any major marketing campaign by Ferrante’s American publisher, Europa Editions, the quartet has sold 1.2 million copies in the United States to date since the first book was released in 2012. “My Brilliant Friend,” which is a bestseller four years after its release, was followed by “The Story of a New Name” (2013), “Those Who Leave and Those Who Stay” (2014), and “The Story of the Lost Child” (2015). Two of the novels are currently on The New York Times Bestseller List, and all four are in the top 10 on the New England Independent Booksellers Association Bestseller List.

How rare is this? Publishing industry executives note that typical bestsellers tend to be widely accessible and offer more suspense or sizzle like Gillian Flynn’s “Gone Girl’’ or E.L. James’s “Fifty Shades of Grey.” This tale is about two ordinary women, is translated from Italian, and is written by an author who refuses to promote the books, insisting the writing should stand on its own.The level of her success “is extremely unusual even for a book not in translation,” says Michael Reynolds, editor in chief of Europa. “For a book in translation, it is rather phenomenal.”

In the Neapolitan quartet, Ferrante’s protagonists begin as two girls in the 1950s living on the wrong side of the tracks in a society riddled with chauvinism, violence, and organized crime. The narrator, Elena Greco, escapes through education. Her brilliant friend, Lila Cerullo, remains stuck, despite teaching herself to read at age 3 and outshining all the other students in school. Readers follow the pair through decades of the exhilaration, disappointment, and tedium of marriage, children, and work.

The writing draws its power from being grounded in psychological and emotional realism. This is not a sugar-coated friendship, nor are these sugar-coated lives. This is, Ferrante writes, “a world in which children and adults were often wounded, blood flowed from the wounds, they festered, and sometimes people died.”

Beyond the story itself, Moronetti says she is also curious about the seeming similarities between Ferrante and her narrator. Both are named Elena. Both are writers. Both grew up in Naples. She also finds that the veil of secrecy around the author increases the intrigue.

For Megan O’Grady, contributing editor and book critic for Vogue magazine, that anonymity is what frees Ferrante to be fearlessly direct and to create such complex, yet relatable characters. “She writes with hard-won honesty about subjects that people don’t feel they can write about with their own identity,” says O’Grady, who was one of the first American journalists to interview Ferrante, which she did via e-mail in 2014. “She writes about hating your mother or your child. She writes about betrayal and sex.”

While all agree that women are clearly driving the Ferrante phenomenon, her fans are diverse. Reynolds says he has heard about African-American grandmothers discussing the novels passionately in Alabama and has seen well-heeled women on the Upper West Side of Manhattan flock to a Ferrante panel discussion.

Many of her readers are old enough to have lived through most of life’s major milestones, but younger readers are captivated as well. Sarah Berman, 25, assistant manager of The Concord Bookshop, read “My Brilliant Friend” at the suggestion of another woman shortly after she had graduated from college. “I understand the intensity of the friendship, and I remember friendships like that,” she says. “They betray each other and love each other.”

The popularity of the novels has not escaped the notice of media executives. A 32-part TV adaptation is being planned in Italy, and Reynolds, of Europa, says that “a very well-known American executive producer” is attached to the project, which suggests the series will be aired later here. Ferrante has fans among the glitterati and the literati alike: James Franco and John Waters are enthusiasts, as are Alice Sebold and Claire Messud. And Oprah, of course.

Ferrante is clear-eyed about the takeaway from her fiction. When asked what she hoped readers would learn from her work in an e-mail interview with The New York Times, she offered this chilling warning. “Even if we’re constantly tempted to lower our guard — out of love, or weariness, or sympathy or kindness — we women shouldn’t do it,” she wrote. “We can lose from one moment to the next everything that we have achieved.”

That’s a harrowing statement, but its resonance for women is undeniable. Ferrante gives “female readers and writers the feeling that she is speaking to them and saying things that they have felt and not necessarily admitted to themselves,” O’Grady says. And they have found it’s something they want to share.

Patti Hartigan can be reached at pattihartigan@gmail.com.