In 2001, when the Swedish Academy awarded Sir Vidia Naipaul the Nobel prize in literature, it described him as the heir to Joseph Conrad: "The annalist of the destinies of empires in the moral sense: what they do to human beings… the memory of what others have forgotten, the history of the vanquished." There are plenty who would have begged to disagree, for Naipaul has regularly attracted criticism, from Edward Said among others, for his dismissive remarks on the cultures of his native Trinidad, on Islam, Pakistan and more. The Masque of Africa is his latest – quite likely last – full-length work of non-fiction. It is a quest through the continent for the spirit of African belief, the belief systems that preceded the arrival of Christianity and Islam – which is very much in keeping with the legacy of Joseph Conrad, who is referenced several times in the book. Already this feels cliched and tiresome; one yearns for the day when an author from outside can approach Africa without invoking the "heart of darkness" mythology. In 1975, Chinua Achebe published an essay attacking Conrad's best-known work as racist and already the novelist Robert Harris has described The Masque of Africa as "toxic". Naipaul's journey across the continent takes him from Uganda, where he lived for a short while in the 1960s, to Nigeria, then to Gabon via the Ivory Coast and Ghana, and finally to South Africa. Along the way, he meets and talks to people about their beliefs. His sources are virtually all African rather than aid workers and expats (you'd be surprised how rare this is). Naipaul discourses with teachers, writers, academics, pharmacists, kings, queens and chiefs, businessmen, friends of friends. That there exists an African intellectual class does not escape him. His sources navigate the complexities and conflicts of their own culture and are able to describe what they have lost with the passing of the old religions. They negotiate their cultural worlds, understand which rules can be broken and which cannot. They can be playful, something more literal minded western writers often fail to grasp, for when it comes to Africa humour is the first casualty. Naipaul gets it. He is dry, often irked, sometimes enraged. He is quite rude. But he is also patient (not a trait often associated with him), engaged, funny, self-reflective and thoughtful. In Uganda, Susan, a poet, has a love-hate relationship with her "Christian" name: "When a person or race comes and imposes on you, it takes away everything and it is a vicious thing to do. Much as I think the west and modernity is a good thing, it did take away our culture and civilisations." Frantz Fanon said the same thing in Black Skin, White Masks and The Wretched of the Earth in the 1950s and early 60s. But there's more. Habib, a wealthy businessman raised as a Muslim, was taught to despise the African religions, something that now angers him. "It was a tool to control our African mind. It is how the imperialists worked." Naipaul is surprised to learn that Habib includes the Islamic world in that. It is a theme that recurs in country after country, as Naipaul notes competing mosques and evangelical churches. The battle for African minds and souls is still on. His is a stately, chauffeured progress, though frequently upon rutted roads. Once, when Naipaul's legs give out on the long walk to see the bones of ancestors in Gabon, helpful locals persuade him into a wheelbarrow. Naipaul finds the elderly wheelbarrow insufficient to the task and clambers out. He finds Africa a struggle. Journeys are almost always longer than he is told; he is kept waiting; diviners all demand to be paid; there is rubbish everywhere; the temperatures are intolerable. It all begins well enough. In east Africa, he explores the ancient kingdom of Buganda, admires the straight roads. In the neighbouring kingdom of Toro, the (British-built) roads curve. He meets the Queen Mother of Toro, who is "full of bounce". He retains his sense of humour in Nigeria, a place where many have been known to lose theirs. His hotel room is unsatisfactory: "The people at the desk began to send me zipping up and down, from floor to floor and room to unsuitable room. It began to seem that a gratuity was called for." He recounts all this in writing shorn of excess, sentences short to the point of abruptness, and he has a wicked way with syntax. After a farcical exit from Lagos airport, he is finally installed in a decent room when the phone rings: "The caller was impatient, on the brink of rage." It is a driver still waiting at the airport to collect him. In Nigeria, he hears spirit legends from the Oba of Lagos, meets the Ooni of Ife and the Oba of Osun, of whom he seeks permission to see the sacred groves. The Oba is accompanied by his wife, the power behind the throne, Naipaul is told. "She considered us one by one. And I felt she liked us." Permission is granted; the grove takes Naipaul's breath away. By Ghana, though, Naipaul is beginning to have a hard time of it. The poor Ghanaians suffer his ire, perhaps because he discovers they eat cats in the south of the country; Naipaul is a big cat lover. His Ghanaian guide, Richmond (a cynical and somewhat self-loathing African), tells him they are killed by being dropped alive into boiling water. Naipaul doesn't care for the Gaa, who make him nervous. He bolts from a meeting with the high priest. Things go further downhill in Ivory Coast, where they eat cats too. He doesn't take to the Ivorians at all – cat eaters, elephant killers, forest wreckers – though he does find beauty in the oft-mocked basilica built by the country's first president, Félix Houphouët-Boigny, a replica of St Peter's in Rome, only bigger. By Gabon, he has recovered some of his equilibrium, and it is here, in the forests, that he finds something akin to Africa's true spirituality. Where Naipaul does both Africa and himself a disservice is in failing to verify much of his information. Somehow, when it comes to Africa, rigour flies out of the window. Naipaul talks of rituals performed using human body parts. Neither Naipaul nor we know if any of this is true. I would treat it with scepticism, as sorcerers famously like to big themselves up by creating a culture of fear. If locals are turning to magic (which they may well be), it is perhaps because such beliefs the world over are the last resort of the poor, the disenfranchised and the dispossessed – in short, those with no other way to change their lives. It is only in South Africa, where the legacy of apartheid proves enduring and unavoidable, and where the sangoma's hollow promises find ever more seekers willing to believe, that Naipaul comes close to this understanding. In another section of the book, he takes at face value a story about the ritual killing of hundreds of people for the funeral of President Houphouët-Boigny. The source is "foreign (but well-placed)". Here the old antennae should be twitching, for there is only one source less credible than a "witch doctor" and that's the "old Africa hand" out to impress a new arrival. Such people exploit the eagerness of outsiders to believe Africans are capable of the very worst. The Masque of Africa is a book for outsiders, for those who may never visit Africa or may know it only superficially. But it is also a book in which Africans themselves may find something to learn. Naipaul is a difficult, imperfect narrator who does not care to be liked, but he is an honest one and doesn't dissemble. Somehow, by the end of it all, and despite his best efforts, I had grown to like him. Aminatta Forna's novels include The Memory of Love and Ancestor Stones.