Before Elena Ferrante’s My Brilliant Friend appeared in English, no one thought it would be a smash hit. The novel and its three sequels, collectively known as the Neapolitan Quartet, follow two women, Lila and Elena, through a tempestuous, competitive, and emotionally intense friendship that doubles as a history of postwar feminism and postwar Italy. Although the books, like Ferrante’s earlier work, were critically acclaimed in the original Italian, editors elsewhere were skeptical that their readers would be interested. In fact, Ferrante’s Italian publisher had opened an American imprint in order to give stateside readers “the possibility of encountering firsthand a major talent like Elena Ferrante.”

Thirteen years after My Brilliant Friend’s U.S. publication, the Neapolitan novels, in Ann Goldstein’s translation, are among the works of literary fiction that contemporary American readers love most: When The New York Times asked some 500 writers last year to vote on the 21st century’s best books, My Brilliant Friend was the winner. Devotees of the novel series have described how intensely connected they felt to Elena, the writer who made it out of her neighborhood in Naples, and her best friend and subject, Lila—the titular “brilliant friend” who, in middle age, has vanished without a trace. In one tribute, Meghan O’Rourke quoted an email that the novelist Claire Messud had written to her: “When you write to me and say you love her work,” Messud said of Ferrante, “I have a moment where I think, ‘But … Elena is my friend!