From Troy to Arcadia, on the high road to elsewhere and the low road to thereabouts, boarding a ferry 'cross the Mersey and hiking the Jurassic Coast, skating away on Duddingston Loch and dynamiting the frozen rivers of Siberia, lured to the summit and drawn to the edge - Alasdair Paterson plots a course at the cruising speed of the flaneur through the ruins of empires, dreams and good intentions. Though pavement cafes still play a part...