Sometime in the next year or two, a woman will give birth in the Lagos slum of Ajegunle, a young man will flee his village in west Java for the bright lights of Jakarta, or a farmer will move his impoverished family into one of Lima’s innumerable pueblos jovenes. The exact event is unimportant and it will pass entirely unnoticed. Nonetheless, it will constitute a watershed in human history, comparable to the Neolithic or Industrial revolutions. For the first time, the urban population of the earth will outnumber the rural Indeed, given the imprecisions of Third World censuses, this epochal transition has probably already occurred.