Travel writers who have long been seeking to earn an honest crust naturally find the present surge of interest in their genre an economic Good Thing. It is not, however, a literary Good Thing. For a decade or more, droves of enterprising travellers have been going to X, Y or Z with camels, snow mobiles, bicycles, land rovers, horses, canoes or hovercraft. If the mode of transport is grotesquely inappropriate, so much the better: eg, carrying a bicycle to the summit of Mount Fuji or riding a horse along the Great Wall of China. Semi-literate volumes ensue, often illustrated by the television team that was all the time lurking in the background. And publishers rejoice, knowing that thousands will now buy any deftly hyped account of a journey to pretty well anywhere.

So, I approached In Xanadu with caution. Was William Dalrymple yet another tiresome band-wagoneer, following Marco Polo from Jerusalem to Xanadu because that seemed a saleable 'stunt'? Was it likely that a hurried journey of 12,000 miles,