It all starts innocently — little girls playing with dolls — but nothing is innocent here. Lila and Elena drop each other’s dolls into a black cellar, where they vanish. Lila declares that Don Achille, the local Camorra chief, has taken them and insists on visiting him to ask for them back. Don Achille is a real criminal, and their meeting is neither funny nor ­charming.

The shock of Ferrante’s writing lies in troubling juxtapositions like this. Children are our private, most intimate and vulnerable selves; they should never meet criminals, those impersonal, brutal and destructive forces. In Ferrante’s series this disturbing conjunction is continual: Crime affects every life, at every level.

Ferrante’s Naples is in thrall to the Camorra, which determines the girls’ behavior toward their classmates (sucking up to Camorra kids), the jobs their boyfriends are allowed (maybe working as an attendant at a gas station on the stradone) and what the girls wear when they come back from a honeymoon (big sunglasses and voluminous scarves, to hide black eyes and bruises). In “Those Who Leave and Those Who Stay,” Lila has married a rich young Camorra lord, had a child and separated from her husband. She’s poor again, working at a nightmarish factory job. During the day, she leaves her son with the neighbors, watching him sink into the morass of ignorance and brutality.

Elena has finished her studies at the university, written a critically successful book and become engaged to an academic. She has joined the intelligentsia and is about to marry into the middle class, yet her life is still rife with limitations. Her distinguished husband is narrow-minded and restrictive, and she finds motherhood numbing. During the struggles of the 1970s between the Communists and the Socialists she turns to politics, only to find that the Camorra rules here too. The violent demonstrations are controlled by thugs.

Ferrante’s writing style is simple and straightforward, headlong almost to the point of clumsiness. Consider this passage about Gigliola, a neighborhood girl who is about to marry Michele, a Camorra lord. Standing in her new apartment, she describes her plight to Elena:

“Michele, she said, is never here, it’s as if I were getting married by myself. And she suddenly asked me, as if she really wanted an opinion: Do you think I exist? Look at me, in your view do I exist? She hit her full breasts with her open hand, but she did it as if to demonstrate physically that the hand went right through her, that her body, because of Michele, wasn’t there. He had taken everything of her, immediately, when she was almost a child. He had consumed her, crumpled her, and now that she was 25 he was used to her, he didn’t even look at her anymore.” He has sex “here and there as he likes. . . . In front of everyone he treats me like a rag for wiping the floor.” The novel’s pace is breakneck, packed with incident. The scenes are lit by emotion, as if struck by lightning.