Everyone knows Christopher Columbus discovered America in 1492 - except a lot of historical fact points to previous voyages by the Vikings to Newfoundland, and possibly even transatlantic odysseys by Irish monks in coracles. And there's a fair body of opinion that Asians either island-hopped or sailed across the Pacific Ocean much earlier.

Alfred Hitchcock used to employ what he called a McGuffin in all his movies, a device to drive the plot but which otherwise had comparatively little relevance to the film as a whole. Travel writers have frequently imitated the master of suspense's technique of selecting an unlikely peg for their story - Tony Hawks' Round Ireland with a Fridge, and A Fez of the Heart by Jeremy Seal being two examples. For Gary Geddes, the McGuffin is an Afghan monk, Huishen, who apparently made his way to the Americas via China 1,000 years before the Genoese adventurer was born.

It's an interesting premise, and for Geddes - an award-winning Canadian poet - a journey made all the more intriguing by starting in Afghanistan in August 2001, a month before the suicide attacks on New York and Washington.

The outline of Huishen's extraordinary journey runs like this: having fled Kabul to escape persecution by marauders from Central Asia, he made his way to China. The records of the Liang dynasty report that he departed for the Americas in AD458, returning in AD499 to recount his wanderings to the emperor and court historian.

While there's not so much in the way of incontrovertible fact in Ten Thousand Things, there's an entertainingly large amount of circumstantial evidence.

Geddes is primarily a poet, and although he writes well, prose doesn't seem to be his best medium. He admits to being a poor traveller ('being on the road heightens my loneliness ... my ideal version of travel would be to visit exotic places all week long but be back in my own bed on the weekends') and at times his footsore weariness seeps into the story. There's no great exuberance, no sense of joy at setting out for undiscovered horizons, but give the man his due: he does see his quest out to the end.

The final scene of the book is on an island off the coast of British Columbia, as Geddes and colleagues search for clues. There's no great denouement or revelation, simply the author's realistic declaration that he's unlikely to find a graffito reading 'Huishen was here'. He's right, but as the man said: 'It's better to travel hopefully than to arrive'.