Review - Coolie Woman: The Odyssey of Indenture, By Gaiutra Bahadur. Hurst £20

The plantations of the British Empire around the world faced a serious problem in the 19th century after the abolitionists succeeded in outlawing the slave trade. Where would the labourers come from? India's vast population offered hope. But British public opinion would not tolerate a repetition of slavery.

So came the system of indenture. People being transported across oceans to work did so after signing contracts, at whose end they were free. It was fair because the worker accepting the contract did so out of choice.

Not really: it was a relationship founded on inequality, between agents of a foreign empire and the most vulnerable people of a subject nation. Notionally, these people chose to work overseas, but as Gaiutra Bahadur's monumental narrative of what began as the story of her great-grandmother reveals, the reality was starkly different. Bahadur blames imperial capitalism, social injustice, and the famines (24 in the last quarter of the 19th century) which caused large-scale migrations of many, including women who had "greater oppression to escape."

One such woman was 27-year-old Sheojari: immigrant number 96153, with had a scar on her left foot. She was four months' pregnant when she left India – her son was born on the ship – and the name of her husband left blank. Bahadur is Sheojari's great-granddaughter. She travels to Chhapra in Bihar, where an elder reproaches her for leaving India, to the archives in Britain, and to the Caribbean. With Coolie Woman, Bahadur lifts the veil of anonymity.

Bahadur studied at Yale and Columbia, and reported on the Iraq war for The Philadelphia Inquirer. In Coolie Woman, she combines her journalistic eye for detail and story-telling gifts with probing questions, relentlessly pursuing leads to create a haunting portrait of the life of a subaltern. "Can the subaltern speak?" the theorist Gayatri Chakravorty Spivak had asked rhetorically. Yes, she can. Through the story of Sheojari, Bahadur shows how.