Husband of a Fanatic, by Amitava Kumar

With a test series looming, Pakistan's cricketers have baulked at playing in Ahmedabad, the capital of Gujarat in western India. Three years ago, up to 2,000 Muslims were massacred as politicians instigated nationalist Hindus to "cleanse" the state after the deaths of Hindu pilgrims in a train fire that now appears to have been a tragic accident. The then Prime Minister, Atal Behari Vajpayee, responded sagely: "Muslims do not want to live with others peacefully."

Amitava Kumar, a professor of English in the US, is the kind of "well-bred Hindu boy" who committed these massacres. Instead, having grown up in Bihar, "India's poorest state", he is now the eponymous husband of a Muslim woman with Pakistani roots. This book began as "an essay on the idea of the enemy", engendering a series of journeys over the India-Pakistan border and the interior boundaries of love and hate, as well as to South Africa, New York and London.

To say anything simple about India is to say almost nothing, and Kumar resists this with distinction. Beginning in Gujarat's refugee camps, he never quite leaves behind a state that once epitomised India's cosmopolitan modernity. His trajectory is from Partition carnage, through the destruction of Ayodhya's 16th-century mosque by the "new Hindus" in 1992, towards the nadir of resurgent India: Gujarat's "state pogrom" against Muslims.

Kumar tells densely wrought stories about forbidden love, his own marriage, tragi-comic border tensions and the poisonous issue of conversion. He confronts his own "contradictions and complicities," most impressively in a story about the blind men of Bhagalpur in Bihar. Here, supposed criminals were criminally blinded by policemen who became high-caste politicians' henchmen, killing with impunity.

The most substantial chapter concerns "long-distance Nationalists", non-resident financiers of the sangh parivar: Nazi-inspired groups of "new Hindus". He contrasts their insularity with the self-scrutiny of a young Gujarati lawyer - MK Gandhi. Kumar follows Gandhi to South Africa to restage his development of a portmanteau nationalism which inspired the independence struggle.

Gandhi's robust sophistication better represents Gujarat than the extremists who regard it as the vanguard for an exclusively Hindu nation. Kumar's returns to the state are compelling, but don't prevent slips, most obviously an assertion that no Muslim businesses survive there. The cumulative insights come from Kumar's equally frequent returns to Bihar, where nuances are brilliantly elaborated.

India prides itself on asking big questions, but avoids Kumar's: what is, and am I, a Hindu? His ambivalent answers are the crucial manoeuvres of modernity. Kumar exposes his, and his country's, complex interiors in this important work of provocation. It requires a political response: a progressive vision of India's future free of the "medieval machismo" of the "new Hindu".