Along the Mekong, from northern Tibet to Lijiang, from Luang Prabang to Phnom Penh to Can Lo, I moved from one world to another, among cultural islands often ignorant of each other's presence. Yet each island, as if built on shifting sands and eroded and reshaped by a universal sea, was re-forming itself, or was being remolded, was expanding its horizons or sinking under the rising waters of a cultural global warming. It was a journey between worlds,...