At first glance the protagonist of James Meek's much-anticipated fourth novel We Are Now Beginning Our Descent seems like the consummate swashbuckling British war correspondent. But, it soon becomes clear, he is actually a modern answer to that lumbering old cliche.

Adam Kellas is a man deep in an existential crisis. Unstable and frustrated by the slow sales of his literary novels he accepts, on a whim, an assignment covering the American invasion of Afghanistan for the liberal British newspaper The Citizen.

On arrival he discovers that the newspaper prefers punchy dispatches that ring with certainty to his nuanced accounts, and his front-row seat at pitched battles and atrocities leave him more numb than inspired.

Profoundly ambivalent about the nature of this war and his own role in its coverage, he finds solace in writing an opportunistic thriller about America declaring war on Europe that would make Tom Clancy blush; it is a plan to make fast money and leave the business.

To complicate matters he has fallen in love with a heat-packing American magazine journalist named Astrid, in what seems like a deplorable lapse in judgment for an avowed pacifist and critic of US imperialism. Ultimately, though, she does not reciprocate his feelings and the pair eventually part, Kellas returning to London no less troubled than when he left it.

More than 14 months later he receives a 29-word e-mail from Astrid and, with a sense of whimsy sharpened by despair, is on board the next plane to America to see her.

Meek, who covered the war in Afghanistan for The Guardian across the same time period, can expect no end of suggestions that his protagonist's story is just a reworking of his own. In response he might point out a 'small, pale man with gingerish hair, glasses and a slightly lopsided smile' who appears momentarily in the novel as a Guardian correspondent and compare it to Meek's jacket photograph before coming to conclusions about exactly who is who in the book.

Apart from that cameo, Meek as foreign correspondent is far removed from this novel and his political biases are certainly nowhere to be found. A story about the new American imperialism would have easily found an appreciative audience at this point in history, but Meek has declined that invitation. One can never quite tell for which Kellas reserves more bile: the pervasive symbols of American imperialism he sees on his daily beat, or what he has come to view as his pathetically conformist liberal revulsion towards them, especially when his tolerance of Afghan society is worn away by its pervasive violence and oppression.

Instead he has produced a work with timeless appeal, one more concerned with truth than ideology. Despite being set against the backdrop of contemporary geopolitics, Meek's book explores the divides that still exist between people in the globalised world and carries a message with resonance well beyond the realm of politics. If cultural divides owe their origins to geography and history, Meek says, they persist by virtue of distance - one that is inherent to perceptions of other cultures, not a mere physical divide. Whether it be Taleban troops on western televisions or invaders' planes flying over civilian villages, observing other cultures from afar emphasises their foreignness and facilitates caricature, fear and violence.

In a journey that stretches across London, Kabul, the American south and back again, James Meek has produced an epic story that faithfully captures the zeitgeist of politics in the Age of Terrorism, while telling the story of distance between lovers, friends and cultures. It is a superb commentary that lends nuance to a story usually written in absolute terms and humanity to what is typically described as the clash of philosophies or civilisations.