Writing her latest novel, Creation Lake, “was the most fun I’ve ever had doing anything in my life”, Rachel Kushner says when we meet in her London hotel. “It was almost like a drug high or a kind of madness. I felt like I was digging a hole to the centre of the Earth and I was not going to stop until I got there.” This from a novelist who used to ride motorbikes at 142mph for kicks. After reading the first line to her friend and mentor Don DeLillo over the phone, she was delighted when he burst out laughing. “Neanderthals were prone to depression,” it begins. “They were prone to addiction, too, and especially smoking.” A novel about prehistory, “the ultimate love story of the coming together of the Homo sapiens and the Neanderthal”, as Kushner puts it, might not sound like everyone’s idea of fun. But she couples her countercultural history of civilisation with a noirish contemporary plot about a former government operative who infiltrates a group of suspected eco-terrorists in south-west France. Written in short, propulsive chapters, the novel intersperses the musings of Bruno Lacombe, the group’s leader, an original soixante-huitard and “anti-civver” who has lived in a cave in the Dordogne for 12 years, with the first-person narrative of spy-for-hire Sadie Smith (not her real name), who, armed with a pair of “notable breasts” and US-military-grade binoculars, is tasked with shaking things up a bit. “I wanted to write an ideas novel that’s not boring, an ideas novel that someone can read and read,” she explains. The idea at the heart of Creation Lake is nothing less than “where we came from and where we are going”, she says simply. It couldn’t be more urgent. As Bruno has it: “Currently, we are headed toward extinction in a shiny, driverless car, and the question is: how do we exit the car?” Attempting to write “a page-turner with long disquisitions on the nature of human history”, was, as Kushner concedes, a bit of “a magic trick”. But it is one she feels she has pulled off, and the judges for this year’s Booker prize agree, putting Creation Lake on the longlist (she was shortlisted in 2018 for her novel The Mars Room). The title, Creation Lake, was inspired by a 17th-century French novel that featured the Carte de Tendre, a map in which all the sites are emotional states rather than physical places, she says. It also happens to be the name of a song by the 1970s rock band the Movies, with whose members her husband, the writer and lecturer Jason Smith, used to hang out. Her publishers are billing the novel as “Killing Eve meets Sapiens”, a neat pitch Kushner bats off immediately: she hasn’t seen the television series – “I’m a snob about TV” – and while she has read Yuval Noah Harari’s bestselling history of humankind, she was more influenced by the work of scientists mapping the genome of the Neanderthal. Kushner herself might be described as American literature’s favourite Proust-loving petrolhead – “gearhead” in the US, she corrects. Her essays – in particular, her earliest, Girl on a Motorcycle – record her love of vintage cars and bikes. She is drawn to glamorous female writers such as Marguerite Duras and Clarice Lispector; she’s “Spinoza with lipstick”, as her husband has quipped. The day we meet she is in “ladylike” mode, in a sharp Bella Freud trouser suit bought for the forthcoming book tour; coincidentally, she is meeting the English designer for supper that evening (Kushner seems to know everyone). “I’m hoping that this novel brings out a different side and I don’t always have to be the car-motorcycle lady,” she jokes. When I catch up with her on a video call back home in LA, she is in her civvies: a black T-shirt and Indian motorcycle cap stolen from her son. In person, as in her essays – which range from celebrations of cult writers, artists and musicians to motorbike racing, from personal pieces about growing up in San Francisco to reportage from a Palestinian refugee camp – she is cool and ferociously smart. She talks in long, fluent paragraphs about her work with the seriousness of one who has spent years immersed in the arts world, but also with the lively curiosity of her novels. While she might seem a quintessentially American writer, she likes to look at her country aslant: her first novel, Telex from Cuba (2008), was a portrait of US expats and Cuban revolutionaries in the 1950s. Her next, The Flamethrowers (2013) – described by James Wood in the New Yorker as “a pure explosion of now” – was split between the 1970s New York art scene and Red Brigades Italy. Only The Mars Room, an inside view of the California prison system, was set close to home. The locations may change, but her focus on political radicals, rebels and outcasts of one kind or another does not. Each novel is an immersion, infiltration even, into theclosed-off worlds of groups who play by their own rules. I’m more attuned to how precious life is now. Like Dolly Parton, I prefer to focus on the good in people Kushner has come to be seen as a gen X Joan Didion, also famed for her street-level portraits of California’s freeways and free spirits. The photo on the front of Kushner’s collected essays, The Hard Crowd, shows the author leaning against her car, and is a nod to the iconic cover of Didion’s 1979 The White Album: Kushner defiantly rock chick in a black miniskirt, Didion in a long hippyish dress. But, as Kushner points out: “Her car was a brand new Chevrolet Corvette that she had just bought off the dealership lot. My car is a 1964 Ford Galaxie.” Now 55, Kushner has handed over the car keys to her son Remy (still asleep in the hotel room upstairs as we have coffee), who got a 1969 Dodge Charger for his 16th birthday and spent the whole summer doing it up. They have come over from France (Remy has been touring Europe with his school orchestra), where the author has been working on a long piece about the French crime writer Jean-Patrick Manchette, whose spirit bled into the new novel. The family have spent the last 14 summers in the Vézère valley, fictionalised as a region called Guyenne in the novel. Both her husband and son are bilingual, and two years ago Kushner decided it was time she learned, too. Back in LA she has early morning Zoom lessons with a teacher in Paris. One day she hopes to read Proust in the original. It was Remy’s deep familiarity with the area’s network of caves – he has been “spelunking”, exploring caves, since he was seven, and now works as a guide himself – that led Kushner underground, literally as well as politically, for the new novel. “There is a whole world inside the world that really does exist, that my son gave me access to through his own knowledge,” she says proudly. The inspiration for Sadie came from real-life espionage stories: in particular, the case of American green anarchist Eric McDavid, whose 20-year prison sentence for acts of eco-terrorism was cut short on the grounds of entrapment after “love letters” from an FBI informant, “Anna”, surfaced; and the British undercover police officer Mark Kennedy, who became romantically involved with various women in the group of environmentalists he had infiltrated for seven years. But she stresses that the novel is not based on real events. “My thing is fiction and I leave that all behind,” she says. “Sadie is my invention.” The emotional heart of the novel for the author is her cave-dwelling sage Bruno. “The question is, where do you go once you have rejected society?” she says. Bruno evolved out of months of research into the genetic mapping of early man, a recent obsession that is still a surprise to her. Although Kushner’s parents are scientists – her father is a molecular biologist and her mother is a retired neurobiologist – she never had any interest in science, she admits. Her parents were also “kind of bohemian”, she adds: big readers, activists and Beats. Contrary to Kushner legend, her family didn’t actually live in a converted school bus, but they would go on long road trips, especially during the winters. Most of the time the bus was parked in the drive of their house in Eugene, Oregon, getting damp – “It rains a ton in Eugene” – and used by the assorted characters who came to stay. Kushner talks of her childhood in two parts: the first in the beautiful Willamette valley of Oregon, which was “very sweet and innocent”, she says. “I had total freedom there.” The second part was spent in San Francisco, where the family moved when she was 11. She “hit the streets” of Sunset, an “unchic” neighbourhood, experiencing a less innocent kind of freedom. The five years she spent in San Francisco shaped the writer she was to become; she returned to the city’s smoky bars and foggy streets in her personal essays and The Mars Room. For all the wildness of her “Sunset girl” years, Kushner always knew she was going to escape, and got into Berkeley to study political economy when she was just 16. “I am the one who lived to tell,” she writes in The Hard Crowd. “Even though I stayed out late, was committed to the end, some part of me had left early. To become a writer is to have left early no matter what time you got home.” After completing an MFA in creative writing at Columbia in her 20s, she lived in New York, working as an editor on art magazines. “I was burnt out on that and wanted to write a novel,” she says. So she moved to Los Angeles and soon after met Smith, a professor at ArtCenter College of Design. They have lived there ever since. “It’s just this vast, unknowable place that’s full of all kinds of different people,” she says. “It’s a great place to be a novelist because I can remain invisible there. I’m just a watcher.” From her study window at home in the Elysian Park area she can see the Dodger Stadium; on Friday nights if the Dodgers win she gets her own firework display. She describes her office as a “poor man’s version” of Freud’s therapy room, which she visited when she was in London for The Mars Room. “I wanted the sense of a teeming set of mysteries and different forms and iterations of human-built beauty in his office,” she says. But instead of “plundering objects from Egypt” she collected knick-knacks from thrift stores in the Central valley. These days she won’t even have a coffee after 10am and needs eight hours’ sleep to write the next day. In the 14-month adrenalin rush that was the writing of Creation Lake, she was working from five in the morning to seven or eight in the evening. She is currently writing a long essay for Harper’s Magazine, ostensibly about how she and Remy recently got into drag racing, but also expounding her Bruno-style thesis on the wrong turn she believes society is taking. “I am strongly starting to suspect that people who work with tools, people who build machines, even if it’s outmoded 20th-century technologies, have a form of richness in their life that people who just scroll phones and use modern computer technology are lacking,” she says. While she is reluctant to be drawn on politics, she finds the “idiosyncrasies and ironies” of French political drama more interesting than those back home. Recent political upheavals in France, and the rise of what Kushner calls “nativism, for lack of a better word”, across Europe, have lessons for America. She was not sorry to see the end of the Biden era: she felt his record was “permanently stained” by his support of Israel in the Gaza conflict. “Israel has allowed polio to take hold in Gaza. They are committing genocide. It is being sponsored by my government. That’s happening now, and unlike Kamala Harris’s plan for the region, yet to be unveiled, there is no speculation required.” As opposed to fellow liberals, “who only know other people who share their own values, and live in New York City or San Francisco and listen to NPR,” Kushner is not afraid of Trump supporters. “I can understand why people vote for him. He’s entertaining. He’s extremely funny. He knows how to shampoo the crowd. He can rile people up. I know a lot of those people but I don’t discuss politics with them. I share other interests with them.” Quoting Bob Dylan in The Hard Crowd, she writes that after “the whole first long ascent of life”, at a certain point we stop living so intensely in the present and become “busy dying” instead. She doesn’t mean it as gloomily as it sounds: “You turn reflective, interior, to examine and sort and tally.” Kushner “absolutely loves” getting older. “I’m more attuned to how precious life is and how much I can learn. Humility is a powerful tool to have on your side, learning to let other people speak.” The novelist’s job, she believes, is to listen and understand, not to judge. “Like Dolly Parton, I prefer to focus on the good in people. I get my one life, and that’s how I want to live it.” Creation Lake is published by Jonathan Cape on 5 September (£18.99). To support the Guardian and Observer, order your copy at guardianbookshop.com. Delivery charges may apply.