The abstract expressionists revolutionised the art world in the late 1940s, only to be displaced by the pop art revolution less than two decades later. This column uses auction price data to explore the life cycles of major painters from the two groups. The abstract expressionists were much older when they produced their peak value works, while the pop artists tended to be most productive in their twenties. The findings provide a systematic basis for dating these revolutions in art markets.