Question marks over the empire's decision: Marianne Brace meets Abdulrazak Gurnah, the Zanzibar novelist on this week's Booker shortlist

The taxi driver taking me to see Abdulrazak Gurnah has hands covered in blue zigzags, birds, triangles and numbers. Such fabulous markings wouldn't look out of place in Gurnah's novel,

Paradise (Hamish Hamilton, pounds 14.99). Set on the East African coast, a world away from Canterbury (where Dr Gurnah teaches), Paradise is peopled by Africans, Arabs, Indians and the dusty warriors who adorn themselves 'with the dedication of brothel queens', their 'tight plaits . . . dyed red like the earth'. Gurnah's fourth novel has now been shortlisted for the Booker, and on the bleak campus of the University of Kent it seems fantastically exotic.

Paradise (the word comes from the Farsi for 'garden') tells the story of Yusuf, bonded to his 'uncle' Aziz in payment for his father's debts. Part slave, part surrogate son, Yusuf accompanies his uncle on a trading expedition fraught with danger. They leave his uncle's property, with its exquisite walled garden, for the dark interior. But if the garden is a formal recreation of heaven on earth, the land beyond is also a kind of wild Paradise. Both are spiced with danger.

A specialist in African literature, Gurnah teaches the Nigerian writers Wole Soyinka and Chinua Achebe, and the Kenyan Ngugi Wa Thiong'o. But on his bookshelves numerous editions of African Affairs and tomes with titles like Towards African Literary Independence intermingle with D H Lawrence, Thomas Hardy and Conrad. For Gurnah also runs a course in Victorian literature. 'Conrad is always interesting to me,' he says, 'primarily because he's writing about the European's encounter with non-Europe. He provides great insights into how Europe saw the rest of the world. Many of the expectations and attitudes of that time - the imperialist narrative - is present in his work. Yet he writes with real irony.'

Zanzibar was still a British protectorate when Gurnah was born there. Once an important location for the slave trade, it is predominantly Muslim with a mixture of races. Gurnah - one of six children - has family roots in both the Yemen and Mombasa. 'My father was a small businessman. He never went to school. But he could write in Swahili using the Arabic alphabet which he learnt at Koran school.'

Brought up on a diet of adventure stories, such as Ballantyne's Coral Island, Gurnah was never given a grounding in the English classics. 'Oh, no, no, no,' he says, with some impatience. 'What postcolonial education allowed you to read was a certain selection of books that were - how should I put it? appropriate, books about the colonies.' It was a literary education fashioned by the tastes of British civil servants who, on quitting the island, donated their personal libraries to local schools. 'No kidding. What they left behind became the fodder for growing boys.'

Following independence, when Zanzibar became 'a shambles of a place where bullies had taken over', schools were shut down. The only way to study was to leave. At 18 Gurnah and his brother set out for Canterbury. It was 1968, 'the time the British were becoming more openly racist and the year Enoch Powell made his rivers of blood speech'. For Gurnah, who did everything from clean hospital floors to teach, it was a shock 'to find inexplicable resentment'. This was the subject he tackled in his second novel, Pilgrim's Way.

In order to write Paradise, Gurnah returned to East Africa - 'not so much to research as to get the dust up my nose.' The book was triggered by a precise image - his father walking slowly across a courtyard. 'He seemed very old. And it occured to me that he had lived through the majority of the European presence in East Africa. He would have known the place before Europeans became all-powerful there. I wondered how the Europeans would have seemed to the people who had been living this way for generations.'

The novel is set just before the First World War, and there are conscious echoes of Conrad's Heart of Darkness. 'It's not an attempt to rewrite Heart of Darkness, but - if you like - (Conrad's) ironical view of the whole enterprise of imperialism is useful to resonate against. This activity that Conrad saw as destructive to the European mind also destroyed the African mind and landscape.' The doomed trading expedition in Paradise embraces failure, sickness and death.

Like Conrad, Gurnah doesn't write in his mother-tongue, but in English. Yusuf is parentless and 'I discovered that Conrad' (another Joseph) 'also lost his parents at 12 and was taken by an uncle.' Yusuf's story not only recalls that of Joseph in the Koran and the Bible, but also suggests scenarios characteristic of the Victorian literature Gurnah teaches. Uncle Aziz's disfigured crazy wife is locked away like an African Mrs Rochester. The boy's rite of passage is determined by the economic confusions of grown-ups in a way that is bound to remind us of Dickens.

Paradise is about trade and barter - even Yusuf's beauty is 'commodified'. Everything has its price, shackling self-fulfilment and freedom of choice. It's logical that a debtor should hand over his only son, that a slave grips tightly to the only freedom he has, which is to refuse the offer of real liberty.

'I wanted to make this seem ordinary,' Gurnah says, 'not catastrophic,' But this ordinariness is extraordinary too in the perspective it allows the reader. Instead of trailing Marlow in his pursuit of Kurtz, we are on the inside looking out. Through Yusuf's eyes we observe the very heart of darkness at a moment in history when the Europeans are pentrating Paradise.

(Photograph omitted)