There is a scene early in Americanah, Chimamanda Ngozi Adichie’s superb new novel, that perfectly captures the tortuous, squeamish lengths white, liberal America will go to avoid causing offence in matters of race. Ifemelu, Adichie’s female protagonist, has recently traded her native Nigeria for the USA. A friend, Ginika, takes her to a clothing store in Philadelphia, and when they proceed to the checkout the cashier asks which assistant helped them, Chelcy or Jennifer. The girls admit to not having caught her name. The cashier enquires whether she had long hair. They both did. Did she have dark hair? They both did. ‘Why didn’t she just ask “was it the black girl or the white girl?”’ Ifemelu says when they finally leave. Ginika laughs at her naivety. ‘Because this is America. You’re supposed to pretend that you don’t notice certain things.’

Fortunately for the reader, sassy and outspoken Ifemelu notices many things, and isn’t afraid to share her views and ruffle feathers. It is while in America that she records her reflections and skewers hypocrisies in a blog called Raceteenth or Various Observations About American Blacks (Those Formerly Known As Negroes) by a Non-American Black. It is also in America that she forgets about Obinze, her childhood sweetheart, and instead acquires a Green Card and a new set of friends and throws herself into university life and the arms of other lovers. Obinze fails to secure a visa and is denied access to the Land of the Free. We follow him first trying to salvage an education in a Nigeria ruled by a military government and plagued by nationwide strikes, and later cast adrift in London where he flits from one menial job to the next, hunts for an elusive National Insurance number and eventually gets caught up in a sham-marriage scam organised by Angolan gangsters. Fifteen years elapse and both characters meet again in Lagos. They may have ‘had a history, a connection thick as twine’, but the question is whether they can resume where they left off, and if not, whether their love can be rekindled.

Americanah is a large, ambitious book that traces its characters’ trajectories from youth into adulthood, while at the same time charting the recent political and cultural changes of developed and developing countries. It’s no small feat, but then Adichie also challenged herself by setting the events of her masterly second novel, Half of a Yellow Sun, against the horrors of the Biafran War. The segments in Americanah focusing on Obinze feel somewhat underwritten, particularly his rags-to-riches arc. However, Ifemelu’s journey to the New World and back is ample compensation. Her discovery of America and her constant struggles with its excesses and contradictions (not to mention her pledge to stay true to her roots and not become an ‘Americanah’) provide our reason throughout for turning the pages. Ifemelu observes with gimlet-eyed clarity and records opinions and emotions with unswerving candour. She revels in the ‘dazzling imperfection’ of Manhattan and loves Baltimore’s ‘scrappy charm’. Sometimes Ifemelu is treated as exotic; at others she is so black as to be invisible. We are given meditations on racial hierarchies and the rise of Obama, and there are several bravura set pieces where Ifemelu snarls at the gushing pretensions and false pieties of simpering fools who claim to ‘understand’ Africa after visiting one African country or reading A Bend in the River.

While Adichie consistently impresses with Ifemelu’s incisive commentary, she falters with the occasional description. Ifemelu’s Aunty Uju – as vivid a creation as Aunty Ifeoma in Adichie’s debut Purple Hibiscus – dotes on her man, the corrupt General, ‘slaving and shaving for him, always eager to fade his flaws’. Such easy alliteration crops up too often: one man is ‘tall and tanned and tactical’; another lives in ‘a gracious and gravelled compound’. Later, as Ifemelu’s support for Obama taints the narrative, Adichie’s prose loses its acerbic edge and veers towards jingoistic mawkishness. On the day Obama becomes the Democrat nominee Ifemelu goes to bed with her lover Blaine ‘and Obama was there with them, like an unspoken prayer, a third emotional presence’.

Such lapses are overshadowed by writing that is, in the main, powerful, heartfelt and evocative. Once again, Adichie excels with her depiction of Nigeria: the ‘sun-dazed haste’ of Lagos reeking of floral perfume, exhaust fumes and sweat; the pot-holed streets full of child beggars and hawkers. The dialogue sparkles, particularly when Adichie lards it with Igbo proverbs and the quaint niceties of Nigerian English, ‘a dated, over-cooked version’.

Chinua Achebe has praised Chimamanda Ngozi Adichie for her fiction, and on more than one occasion she cites his novel Things Fall Apart. Americanah demonstrates that Adichie is starting to resemble her literary idol – fearlessly tackling weighty themes of race and identity, and ably challenging the West’s ingrained perceptions of African life and culture. In short, then, she is a writer of huge talent who just keeps getting better.