A Mercy, By Toni Morrison

"To be given dominion over another is a hard thing; to wrest dominion over another is a wrong thing; to give dominion of yourself to another is a wicked thing". This is the message of Toni Morrison's new novel; her ninth and one of her best. Set in the 1680s, the story centres on the household of Jacob Vaark, an Anglo-Dutch trader who has created a homestead in the harsh Northern territories. It is told from the perspective of the young women who have washed up there from other places: his mail-order bride Rebekka, who has endured the fearsome Atlantic crossing from England; Lina, a native American woman whose tribe was decimated by smallpox; Sorrow, the unhinged daughter of a sea captain; and Florens, a wild young black woman who Vaark, despite his distaste for dealing "in flesh", has taken on as payment for a bad debt.

This was the sort of family circle that could only have come together in those "disorganised" early years of settlement, when slavery had not been institutionalised. Morrison has said she wanted to depict the pioneers that do not feature in popular history. Her characters are like migrants today, she says: "ordinary people who came without help", struggling to survive in the wilderness. The supporting cast includes white servants whose terms of indenture are indefinitely extended, well-meaning priests, as well as witch-hunters, intolerant Presbyterians and self-indulgent Catholic slavers. At the centre is Florens, abandoned by her mother and desperate for love. Her obsession with a free African blacksmith becomes her tragedy.

Morrison has said she was surprised at her interest in this period. But in the context of her oeuvre, which could be described as an attempt to chronicle the African American experience from an African American perspective, A Mercy makes perfect sense. It could be seen as a prequel for the other books, both setting the scene for - and enriching our understanding of - those that follow, particularly Beloved. For those familiar with Morrison's work, there are reoccurring themes here.

The youthful Florens, whose irrepressible spirit and love of "prettifying" brings her to the attention of her predatory owner, is reminiscent of other wanton women in Morrison's books: outlaw figures like Sula, rejected by communities because of their ungovernability, but who end up as truth-tellers and catalysts for change.

Slavery is again the focus here, as in Song of Solomon and Beloved. But A Mercy expands its definition to explore other forms of enslavement, imposed by religion or romantic love. Although Morrison writes about "the danger and the promise of men", which enmeshes her female characters, it is relationships between women and their children that she returns to again; for Morrison, this is the love that endures.

Morrison's writing has been accused of "difficulty", and some recent work – such as Paradise – has demanded tenacity. But A Mercy is an easy and seductive read, though its structure has much in common with earlier, more challenging, offerings. As with Love, its narrative structure builds, "like a crystal"; the characters' stories gradually converge around central themes to create the power of the overall narrative, and so the ending is both devastating and satisfying. As always with Morrison, the language here is so rich that it takes a careful read in order to fully appreciate the density of images and vivid specificity of the detail.

A Mercy is a stunning and significant book that fills an essential gap in the American story. Explaining the raison d'être that sustained her even as a young writer, Morrison has said: "No African-American writer had ever done what I did... even the ones I admired – which was to write without the White Gaze... This was brand-new space, and once I got there, it was like the whole world opened up, and I was never going to give that up."

In America, Morrison has long since ceased to be merely a literary figure. Now she is a political grandee whose work and opinions are intrinsic to any debate about race. A Mercy, like all her books, will be compulsory reading for the black intelligentsia. Her support will be gratifying for Barack Obama, who is said to have courted her initially. She took her time, leaning towards Clinton, before concluding: "He is the man for the time". Morrison is an astute commentator, who usually says the right thing but rarely the easy thing. Giving dominion of herself to another is simply not a feature of her work.

Andrea Stuart's 'Josephine: the rose of Martinique' is published by Pan

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