Joyce Carol Oates is on her feet in her study, looking out over woodland in rural Princeton, New Jersey, while her maine coon, Zanche, sprawls atop a swanky white cat tower. We are speaking on video and Oates pans around the room – large, book-lined – to show me it. She lets the camera linger on Zanche, who is amply provided for – she also has her own “catio” garden. “She hopes we won’t interfere with her nap,” Oates says, in a voice that sounds mildly warning. She is friendly, but not in a way that makes her less forbidding.

We are speaking before the publication of her novel Babysitter, inspired by a serial killer who murdered children in the 1970s in the suburbs of Detroit, where Oates lived at the time. She is 84, but her work remains exceptionally relevant. The film adaptation of her 2000 novel Blonde, a fictionalised account of the life of Marilyn Monroe and “the most difficult novel” she has written, is to be released on Netflix next month, while Babysitter is unflinching in its detailing of sexual assault before the #MeToo era. According to her publisher, it is Oates’ 61st novel, although no one seems certain, least of all Oates. She waves away the question as if counting is for people who have nothing better to do.

“It’s like: ‘How many nice meals have you prepared?’ You know, for your family or friends. You take some time to make a nice meal, but you don’t necessarily remember. Maybe it sounds ridiculous, but I’m totally immersed in the work I’m doing today. Every time I write, it’s like the first time,” she says.

The approach has yielded so many books that the epithet routinely attached to Oates is “prolific”. Unfortunately, this suggests that the salient feature of her output is its quantity. Does she mind? “I guess it’s just true. It’s just a fact,” she says. “I never thought that I would even publish one book. If you publish your first when you’re quite young, you feel: wow, maybe there will never be another one. And it was sort of one book at a time. Or one project at a time. ‘If I can just get this finished …’ I guess I just kept on with that.”

She seems to regard the whole business as unremarkable, yet the maths is mindblowing: nearly 60 years of writing, divided by all those novels, plus novellas, short story collections, essays and book reviews. And it is not as if she is a recluse. She teaches creative writing at Princeton and this morning has already taken a walk with a group of friends. In the evenings, she watches TV and films, often with Zanche stretched beside her, and she tweets. She has spoken before of her daily runs, an hour each evening, in which her mind “flies” with ideas. These have slowed a little. “Well, I usually run and walk, run and walk,” she says. But her writing metabolism has not faltered.

Oates says that Babysitter – a thriller that is poetically watchful of the mind of its protagonist, especially as she approaches turning points – “is also based on the risks we take in writing: spending years of our life on a project” without knowing what, if anything, the time will yield.

You would think Oates had no such worries now; she has been acclaimed as a writer since her fourth novel, Them, won the US national book award in 1970. She has five times been a Pulitzer prize finalist and is often considered “America’s foremost woman of letters” (a description thought to have been coined by John Updike), celebrated for dark and precisely observed fiction that splices violence and tenderness. Even Blonde, one of those Pulitzer finalists, is a kind of horror in the way it explores the division between Monroe as a performer and Monroe as a person. Yet she steadfastly writes “professor” as her occupation when filling in forms, never “writer”. “Well, is that a profession?” she asks. For Oates, it seems more a way of life.

As a young child, growing up on a farm in Millersport, New York, she doodled stories, often featuring chickens and, yes, cats with fur of many hues. It was her paternal grandmother, Blanche, who, seeing her granddaughter’s sympathy with storytelling, organised six-year-old Oates’ first library ticket. She bought her a toy typewriter and then, at 14, a real one. Oates has never written a novel on a computer, nor would she. “If James Joyce had written Ulysses on a word processor, he might still be writing it. Because you can always keep revising and maybe Joyce would never have finished.”

It was Blanche, “my only relative interested in books”, who gave her Alice’s Adventures in Wonderland, for her ninth birthday. Oates has described that novel as “the singular book that changed my life, that made me yearn to be a writer”.

She turns to the shelves behind her. “The book is back there. It’s about this big,” she says, shaping a standard-sized book with her hands. “I used to think it was this big,” she says, throwing open her arms, as if Alice’s changes in perspective have been Oates’, too, as if her own imagination were rearranged in that first encounter. “It’s really a normal book. But to me it was so, so monumental.”

She is on her feet again, reaching across her desk for a framed photographic montage – assembled by her friend, the late Gloria Vanderbilt. It puts Blanche front and centre. She points to the top-right corner of the picture. “There’s a little picture of me as an adult up here, sort of looking … There’s some flowers and trees … Gloria understood that my grandmother was central to my life, so she put her in front. And then my mother. And then my father. They are all in my study with me,” she says, then pauses. “Though I’m all alone now.”

Oates’ first husband, Ray Smith, who for more than 30 years edited Ontario Review, a literary and arts journal that he and Oates founded, died unexpectedly in February 2008, while being treated for pneumonia. They were “inseparable companions”, yet they might never have met if Oates, at 21, had not taken “a very big risk”, the sort “where somebody might say: ‘Why did you do that?’”

She was expected to go to Cornell University with her boyfriend of three years, but she read an article about the University of Wisconsin and “something came over me”, she says. “And I thought: ‘I’m going to this other place.’”

At the time, she could not pinpoint Wisconsin on a map, but the “complete plunge” changed her life. “I would probably have gotten engaged and married to a different person, not a literary person, and it would have really been a mistake,” she says. Instead, she met Smith; they were living together within a month and married within three.

“The stark, implacable, unspeakable, indescribable terror of aloneness” Oates felt after his death is captured in her 2011 memoir, A Widow’s Story. But, at the end of the book, she alludes to “a stranger” – in fact, the neuroscientist Charles Gross, a Princeton colleague whom Oates had met at a dinner party. Just over a year after Smith died, they married. But, in 2019, Gross, too, passed away, from cancer.

I can’t help wondering if the raw grief that Oates logged in the memoir helped her through the pain the second time around; whether the “survivor’s guilt” she detailed grows or subsides. “I can’t really talk about it that much,” she says.

Well, I say, trying to sound positive, the love contained in the memoir is wonderful: absolute and immense. “I was close to my parents also. I think we shouldn’t talk about this,” she says. She looks distraught as she pats at tears. Eventually, she says: “I have my kitties.” (As well as Zanche, there is Lilith.) “It’s hard to talk to widows. It’s hard to know how to talk to anyone,” she says.

I mention Twitter, to change the subject. “Oh, I don’t think about it too much. Twitter is very ephemeral,” she says. Oates was criticised recently for tweeting the words of an agent who told her “he cannot even get editors to read first novels by young white male writers, no matter how good”. Statistically, publishing retains a strong bias towards white writers, but Oates did not amend her remarks after they made headlines, although she did apologise last year for suggesting that the pronoun “they” would never become “part of general usage”. Does she worry about saying the wrong thing, or about the consequences of what she tweets?

“Well, Ricky Gervais, I think, has the right attitude. He’s very, very funny. He’s brilliant as a comedian. He says somebody can be offended, but it’s just their own opinion … All these things are like hornets. If you don’t really care about it, what’s the difference?”

One difference might be that Oates’ reputation carries a burden of responsibility; that while she regards Twitter as ephemeral, a passing tweet from a literary great can have a lasting impact on others – something she herself acknowledged when she apologised for the remark about pronouns.

“Well, I don’t really care. It’s not anything I’m thinking about,” she says. I suspect that, although the subject has changed, Oates’ thoughts have stayed with Ray, and Charles, and her parents, and others, because she sounds as if she is grieving when she says: “I have a personal life and I have things going on in my life that are important. You know, involving people who are ill or dying. I mean, a lot has happened in real life. To care about a screen or social media, that’s something you do, I think, when you have time for it.

“As soon as a hospital crisis comes in your life, you totally forget about this stuff. When my husband Charlie was ill – six months … I mean, there’s just months and months where nothing else matters. And those times in our lives that you see what really matters, I don’t think people’s opinions are very important. I don’t even care. A matter of surviving for another day,” she says, with an anguished laugh. “Am I still going to be alive tomorrow? Dealing with that existential reality and taking care of people who need to be taken care of? So, if I have energy for anything, it’s for my writing and my work.”

A few days later, still wondering whether A Widow’s Story has encumbered Oates, by putting her grief in the public domain, or whether it has helped her, I write to ask. But she replies: “What is there to say about loneliness? Some people report that they feel lonely within their own marriages. Who can say? It’s all so subjective.” Then she adds, brightly, whether in self-talk or advice to others: “Keeping busy, occupied, particularly with work outside the home, like teaching, is probably ideal. Plus domestic pets!” And she sends a picture of Zanche enjoying her catio.

• Babysitter by Joyce Carol Oates is published by 4th Estate (£18.99). To support the Guardian and Observer, order your copy at guardianbookshop.com. Delivery charges may apply