Is inequality largely the result of the Industrial Revolution? Or, were pre-industrial incomes as unequal as they are today? This article infers inequality across individuals within each of the 28 pre-industrial societies, for which data were available, using what are known as social tables. It applies two new concepts: the inequality possibility frontier and the inequality extraction ratio. They compare the observed income inequality to the maximum feasible inequality that, at a given level of income, might have been ‘extracted’ by those in power. The results give new insights into the connection between inequality and economic development in the very long run.IMHO, the concept of inequality possibility frontier is brilliant and relevant for historians and development economists.