In placing the Haqqani network not so much at the centre of the extremist nexus but at its origin, this book makes an important contribution to our understanding of Afghan and Pakistani militant groups. And it has obvious implications for the terms of any eventual peace settlement, which could well see the Haqqanis taking control of its south-eastern heartland.

It is weaker in discussing the extent to which Pakistan and its ISI spy agency continue to run the Haqqanis, relying on historical accounts dating back to the anti-Soviet Jihad brought up to date with weakly sourced American allegations. To be fair, no one else has much of an insight into Pakistan’s current attitude towards its long-standing allies.

But it sets out clearly what should be a key question facing Western officials scrabbling for a face-saving peace deal: Can the Taliban of Mullah Omar sever its ties to al-Qaeda – a red line in any negotiation – when it is clear that the Haqqanis remain so close to bin Laden’s terrorist outfit?

Technically the Haqqanis have sworn loyalty to Mullah Omar and say they will stand by his decision but this book makes clear that it might not be as simple as that, and to give up al-Qaeda would change the trajectory of decades of history.