Most people assume the crisis is temporary, not unlike the economic downturn that coincided with Florence’s college graduation — born in the mid-1980s, she’s a millennial. But her son, Willing, watches the business news and has an uncanny sense of how all the pieces fit together. As one character puts it, “Complex systems collapse catastrophically.” Within a few years, Florence’s family will have lost literally everything they once thought they owned.

Image Lionel Shriver Credit... Sarah Lee

It’s probably already obvious that Shriver isn’t the kind of writer who lets her themes rise gently to the surface. She seizes them with an almost animalistic ferocity and interrogates them for all they’re worth. Her smart, satirical fiction is old-fashioned in that it serves as a vehicle for investigating political and social questions, but it’s also almost uncannily of its moment. A few years after the massacre at Columbine High, “We Need to Talk About Kevin,” her breakthrough novel, examined the psychology of a mother whose son ­committed a school shooting. “So Much for That,” which appeared just as the Affordable Care Act became law, chronicled the bankruptcy of a family whose health insurance is laughably inadequate to cover their bills for a devastating illness. More recently, “Big Brother” delved into the contradictions surrounding the popular perceptions of obesity and weight loss. Though these books are nominally about very different subjects, they pulse with the same undercurrent of rage at the hypocrisy of American mores and the dysfunction that plagues our broken social contract.

Shriver has always seemed to be at least a few steps ahead of the rest of us, but her new novel establishes her firmly as the Cassandra of American letters. Like David Mitchell’s “Cloud Atlas” or Margaret Atwood’s “Oryx and Crake,” “The Mandibles” depicts a world that is at once familiar and horribly altered. What’s most disquieting isn’t the disruption of daily life (though it’s devastating) but the ease with which people adapt to their new circumstances. Shriver’s dystopia is imagined as minutely as a pointillist image, with every detail adding another dot to the overall picture. The devolution of civilized society happens slowly at first, then all at once. The niceties of life gradually disappear: citrus fruit, olive oil, toilet paper. Streets are no longer cleaned; once-upscale storefronts are boarded shut; even Zabar’s is vandalized and looted. Florence stops ironing to save electricity and wears a bandanna to disguise her unwashed hair. Willing gives away his beloved spaniel while the family can still afford to feed it, knowing that by the time they won’t be able to, no one else will either. Homeownership, the foundation of the American dream, proves to be the longest-lasting currency. Eventually, most of the Mandible clan will seek refuge with Florence in East Flatbush, including her sister, Avery, and brother-in-law, Lowell, a former economics professor at Georgetown who failed to predict the current situation and still doesn’t comprehend it. (Tenure is among the luxuries that society can no longer afford — Lowell has been summarily sacked.) Then Florence’s grandfather, Douglas Mandible, appears on the doorstep, now 97 years old and saddled with a wife suffering from dementia. All that remains of Bountiful House, his once-grand estate, is the silver service, each piece engraved with an M.

The M stands for Mandible, of course, but it might just as well stand for Money, the novel’s true subject. The Mandible descendants never laid hands on the cash, but it was always there in the background, silently working its mysteries on their psyches. “A family fortune introduced an element of corruption,” we are told early on. Its bite is felt in subtle ways. Back in the old days, Florence’s father, Carter, wondered if it was fair that he and his sister, Enola, would have to divide the fortune equally, considering that he had three children (Florence, Avery and their younger brother, Jarred) and four grandchildren, while Enola, a novelist, remained single, with no dependents. After the Renunciation, as the economic collapse is called, even a small amount of money can be psychologically transformative. When Lowell heads to the supermarket after finally receiving a summer’s worth of back pay, the sensation of “trouser pockets that bulged with banded cash” makes him feel like “a real man” for the first time in months. But his buoyant mood is pierced by the discovery that, thanks to inflation, the cash won’t even cover the groceries in his cart.