A new book by Robert Putnam, whose ‘Bowling Alone’ popularised the concept of social capital, examines growing income inequality in the United States and argues that the affluent and the poor now increasingly live in worlds completely isolated from one another.

The concentration camps were extermination camps: when prisoners were not immediately murdered, they were subjected to a regime few could long survive. Yet this is not so unprecedented in human history. Eighteenth century slaves were not only routinely subjected to the most sadistic punishments but also worked to death.