Jokha Alharthi’s second novel, Celestial Bodies, may have its roots in rural Oman – its irrigation canals and high desert nights, its cool back rooms and busy courtyards – but it was born in Edinburgh. Alharthi was studying for a PhD at the university, she had an eight-month-old baby, and she and her husband had had difficulty finding a place to live and so were renting a small flat from week to week. Her stress was compounded by the fact that, although her PhD was in classical Arabic poetry, she was expected “to write fluent English, and to write fluent essays, and I was like, I never did that! I never did that. So I just came back to the flat one night and got the baby to sleep, and just sat there with my laptop thinking about – not exactly Oman, but a different life, and a different language. And because I love my language so much, I felt the need to write in my own language. So I just started writing.” She had already published one book, Dream, “a love story, kind of”, and for a long time had been thinking of another, with snatches of ideas and characters and places. “It wasn’t all clear in my mind, but I kept thinking about them, and also about the traditional ways, which are rapidly vanishing in Oman.” But she “hadn’t started yet, until that moment, when it was a really difficult moment for me. So it was like going back to my mother’s womb again, to feel warm, and secure. The novel – I don’t want to say it saved me, it’s a big word – but kind of.”

Just over a decade later, in May this year, Celestial Bodies won the International Man Booker prize. Alharthi beat finalists including last year’s winner, Polish bestseller Olga Tokarczuk, and joined previous winners including Korean author Han Kang; it was the first book from any Arab country to win. We meet the morning after, in a bright many windowed room on the top floor of the headquarters of the Royal Institute of British Architects in central London. Alharthi sits next to her translator, Marilyn Booth, who remembers that the translation, too, began in Edinburgh: Alharthi had not yet finished her PhD when her supervisor retired, and Booth took over (she is now professor in the study of the contemporary Arab world at Oxford). “She brought me her novel. And I just really loved it, and wanted to translate it.” Booth was so keen that she completed the translation before they had a publisher lined up, “which is not always a good idea”, she says. Celestial Bodies is the first novel by an Omani woman ever translated into English, and the prize, £50,000, is split equally between them.

The book tells the story of three generations of a family from a village called al-Awafi. There are three daughters, their father and mother, their children and their husbands’ parents. The birth of a child called London (the capital of a foreign city, a Christian city no less, whisper appalled neighbours and relatives) is the hub from which all sorts of spokes radiate, then spin with speed and impressive control: within six pages we have been presented with an animating tragedy, and a memorable account of a woman giving birth, “standing as tall as a grand mare”. Alharthi’s characters are pleasingly contradictory and fallible, irreducibly individual. A doting new father brings cases of baby food for an unweaned infant, an act that is “unnecessary and slightly disgraceful”; a former slave locked away as “mad” by an embarrassed daughter calls out, whenever she hears a noise in the courtyard, “I’m here, I’m here, I’m Masoud and I’m in here”.

To say that Celestial Bodies is a multi-generational saga simplifies what Alharthi has done, which is also to tell the story of how Oman has changed over the last century, from a traditional rural patriarchal society where Islam was complemented by Zār spirit worship, and which was among the last countries in the world to abolish slavery (in 1970), to an urban, oil-rich Gulf state. And she has done so in a form that shifts from voice to voice, viewpoint to viewpoint, decade to decade, sometimes within a single paragraph or sentence. It is no surprise that, as well as 10th-century Arabic poets such as Abū al-Tayyib Ahmad ibn Husayn al-Mutanabbī, and the more recent Mahmoud Darwish, Alharthi counts among her favourite writers Gabriel García Márquez, Milan Kundera, Yukio Mishima, Yasunari Kawabata and Anton Chekhov, and that the first piece of fiction she published, at 18, was a short story. She has since written three collections of stories, which have been translated into five languages, as well as children’s books.

Celestial Bodies was first published in 2010, and it has been a “lucky book” says Alharthi, who is 40 and is in person as direct and unshowily confident as her prose. “I think books are like people, some have lucky lives, and this book got a lot of attention.” The critics loved it, a master’s thesis has been written about it, and last year a critical study. She does almost all of our interview in fluent and authoritative English, but now she turns to Booth: “I want to say this in Arabic if you don’t mind, to put this in precise words – I don’t want to get it wrong.” “Some people feel that touching upon a sensitive topic like slavery is stirring up the past in a way that isn’t appropriate now,” says Booth after a moment, “because Oman is another country, and slavery is something of the past. But she’s saying that that’s what literature does – it’s to think about the past, to think about history.”

Alharthi grew up immersed in history and especially in Arabic literature. An uncle was a poet and travel writer; her grandfather was a poet who “when I was a child, in every situation would recite verses from Al-Mutanabbī to justify his position” – just as one of her characters, Azzan, does, to his beautiful Bedouin lover, who finds it increasingly alienating and irritating. Booth, who studies modern Arabic language and culture, and whose Arabic is in fact Egyptian Arabic (she has never been to Oman, and had to ask Alharthi to send her photos of typically Omani things she had not come across before), found these poems, with their double meanings and referents that stretch a thousand years into the past, by far the most challenging sections to translate. “She hated me for it!” laughs Alharthi.

When Alharthi’s mother was growing up in the village of Al-Qabil there was no schooling beyond basic reading and writing for anyone, male or female, unless you went to the capital, Muscat, so she taught herself poetry, reciting it as she went about her daily chores. By the time Alharthi and her siblings were born things had changed, though there still wasn’t a kindergarten, so her father, who was the local governor, forged their birth certificates so they could start school early. “He thought we were too smart to sit at home.” Alharthi, who now lives in Muscat and teaches classical Arabic literature at Sultan Qaboos University, is one of eight sisters and four brothers. And where do you come? “OK, let me see,” she counts them off on her fingers, under her breath. “I think I’m number four.” The others have gone on to work in a wide range of jobs, from oil company employee to a brother in the foreign ministry and a sister who runs a communications company. Alharthi herself is married to a civil engineer and they have three children.

One of the many striking things in Celestial Bodies is the way Alharthi refuses easy assumptions about power, and people’s roles in the world. There is a moment, for instance, where she focuses on the childhood of one of the main characters, a matriarch, Salima, who started off as a poor female relative. Then she was not allowed to eat or be clothed as an equal with rich relatives, but at the same time she was not allowed to mix with the servants, to bathe like them, or dance as the slave girls do. Adult Salima cannot abide Zarifa, a former slave from her son-in-law’s family, who runs the household, has the love and devotion of her supposed master and his son, and has the power in all but name. “For me it’s always complicated,” says Alharthi, “the relationships are complicated, and people claim their authority wherever they are. A lot of women are really strong, even though they are slaves actually, but they still can be strong.” Each chapter is named after the person from whose point of view it is told, but it is interesting that the only one who speaks in the first person is a man, Abdallah – again supposedly the inheritor of riches, a businessman, the head of his household, the man in a man’s world who ought to have all the power. “But Abdallah doesn’t!” says Alharthi, partly because of old hurts, partly because of the intensity with which he loves someone who does not love him back, partly because his world is changing so fast, partly because of the strength of the women who surround him. “You’d assume that the first-person character is the one who’s got some authority,” adds Booth, “and he’s really the most vulnerable.”

How does Alharthi feel about the much wider readership this prize might give her? She is silent for a while. “I don’t know, it is strange … yanni” – she turns again to Booth; English phrases pop like bubbles out of urgent Arabic. “It’s wonderful to have a bigger readership,” says Booth at last, “and to have readers everywhere, but it’s also a slightly strange feeling, because these are characters that came out of her mind. They developed within her own thinking and they’re going out into the world and other people are reading about them and thinking about them, and it’s slightly hard to let go.” Or, as Salima says about her daughters: “We raise them so that strangers can take them away.” There is the further point of culture, says Alharthi, which is that “when it was published in Arabic, the Arabic audience in general and the Omani audience in particular can easily relate to the novel” – and non-Arabs cannot really be expected to feel the same sense of recognition. “But I still think that what attracts us to literature is not that it’s familiar to us, it’s that we can relate to the universal value in it. Even if it has a very strong mahaliya” – “localness”, supplies Booth – “still I hope that international readers can relate to the universal values in it.”