Floods come quickly upon villagers in the Ganges and Brahmaputra delta, particularly when dams on the other side of Bangladesh's land borders are opened without warning. People seek refuge on roofs, only to be at risk from deadly bites of water-shy snakes. From Delta: The Perils, Profits and Politics of Water in South and Southeast Asia, a photographic survey by Daniel Schwartz of life in these impoverished yet resourceful delta regions. Thames and Hudson, £28.