Every river deserves its own history. The seven rivers in this narrative were chosen because they are major rivers that magnify the common qualities of these great natural arteries that run through civilization. The Nile, Danube, Niger, Mississippi, Ganges, Yangtze, and Thames are all "world rivers” by virtue of the roles they have each played in our shared and conflicted world history. They have served as the power bases for empires and have been fought over as frontiers. Their river basins—those great systems of tributaries and groundwater all flowing to the main river—have been plundered for their gold, timber, salt, oil, rubber, and their people. Vast networks have been forged between these rivers, such as the deadly "middle passage” of the slave trade linking the Congo and Mississippi basins. And rivers themselves have always had their own logic: their natural beauties, their floods, droughts, water-borne diseases, their tendency to silt up and mutate into marshland, their marshy subsidence below the cities of the unwary, their changes of course, tipping points and disappearances. These rivers have shaped our lives, just as we have shaped theirs. What follows is the story of humanity, in seven rivers.