In his latest absorbing travel epic, Thubron (In Siberia; Mirror to Damascus) follows the course or at least the general drift of the ancient network of trade routes that connected central China with the Mediterranean Coast, traversing along the way several former Soviet republics, war-torn Afghanistan, Iran and Turkey. The author travels third-class all the way, in crowded, stifling railroad cars and rattle-trap buses and cars, staying at crummy inns or farmers' houses, subject to shakedowns by border guards and constant harassment even quarantine by health officials hunting the SARS virus. Physically, these often monotonously arid, hilly regions of Central Asia tend to go by in a swirl of dun-colored landscapes studded with Buddha shrines in varying states of repair or ruin, but Thubron's poetic eye still teases out gorgeous subtleties in the panorama. Certain themes also color his offbeat encounters with locals most of them want to get the hell out of Central Asia but again he susses out the infinite variety of ordinary misery. The conduit by which an entire continent exchanged its commodities, cultures and peoplesThubron finds traces of Roman legionaries and mummies of Celtic tribesmen in western China the Silk Road becomes for him an evocative metaphor for the mingling of experiences and influences that is the essence of travel.