The Punishment Of Virtue, by Sarah Chayes

There has been a deluge of books in recent years that could be subtitled: "I fought with the Mujahideen and won." The author, who is usually a foreign correspondent, will have first conspired at Greens Hotel in Peshawar, then slipped over the Afghan border in disguise and seen action at close quarters. After taking part in the fall of Kabul or Mazar-i-Sharif, the narrator will end his story with a pious reflection on how neither the British nor anybody else has ever been able to hold Afghanistan.

Sarah Chayes's account is a welcome antidote to such tales of derring-do. An American journalist, she stayed on in Afghanistan to help rebuild the country after the allied invasion and has witnessed the lack of any clear US policy - and has spotted the reasons.

She notices that staff are rotated after a few months on a "hardship station", with a resulting lack of continuity or purpose. The military have no good Pashtu translators, or even a clear sense of the clan divisions in a country where tribal loyalty is so important. The result? "The sails are always luffing," and America remains irresolute in the face of the warlords it relies on, and of the self-fulfilling presumption that the country is inherently ungovernable.

Nor do civil and military divisions seem to talk to one another (literally - some officers end up having to bring their own walkie-talkies). At comical moments, Chayes finds herself having to act as go-between for an occupying force every bit as tribal as the Afghans.

There are darker passages, notably those where Chayes exposes herself, with considerable courage, to political rivalries in Kandahar, the most dangerous place she could have chosen to live.

At the heart of the book is an account of her unexpected friendship with the police chief there, Zabit Akrem. As a "liberal humanitarian", this is not instinctive for her, and the story of her growing appreciation of Akrem's virtue is cut abruptly short; he was assassinated in 2005.

Chayes' message is that the allies face an extraordinarily resolute enemy in the Taliban and need to be equally clear-sighted. Far from being ungovernable, the Afghans have a long tradition of local democracy; it should be built on, rather than relying on the thugs and warlords who killed her friend. This passionate and engaged dispatch from the field is in the best tradition of grassroots reporting; it is, quite simply, the best book on Afghanistan since the invasion.