It started as a daydream. Poring over a map of the world at home one quiet Saturday afternoon, Ewan McGregor - actor and self-confessed bike nut - noticed that it was possible to ride all the way round the world, with just one short hop across the Bering Strait from Russia to Alaska. It was a revelation he couldn't get out of his head. So he picked up the phone and called Charley Boorman, his best friend, fellow actor and bike enthusiast. 'Charley,' he said. 'I think you ought to come over for dinner...'

From London to New York, Ewan and Charley chased their shadows through Europe, the Ukraine, Kazakhstan, Mongolia and Russia, across the Pacific to Alaska, then down through Canada and America. But as the miles slipped beneath the tyres of their big BMWs, their troubles started. Exhaustion, injury and accidents tested their strength. Treacherous roads, unpredictable weather and turbulent politics challenged their stamina. They were chased by paparazzi in Kazakhstan, courted by men with very large guns in the Ukraine, hassled by the police, and given bulls' testicles for supper by Mongolian nomads.

And yet despite all these obstacles they managed to ride over 20,000 miles in four months, changing their lives forever in the process. As they travelled they documented their trip, taking photographs, and writing diaries by the campfire. Long Way Round is the result of their adventures - a fascinating, frank and highly entertaining travel book about two friends riding round the world together and, against all the odds, realising their dream.