Abstract
The definition of income consists of two parts: the flow of 'new' income, from work as well as capital, plus the change in the value of net wealth. These jointly determine the 'consumption possibilities'-that is, the income-in a given period. This means that the study of income inequality requires paying attention to both the distribution of the income flow and the distribution of wealth. This chapter sketches how the research program initiated by and associated with the work of Thomas Piketty has brought this insight back to the center of the inequality debate. It also shows some of the ways in which key results from this work have changed the way we think about long-run income inequality.
