Paul Davidson was a critical figure in the preservation of John Maynard Keynes’s ideas, sticking with them when they were out of fashion. He was also key to the survival of the Post Keynesian school. Davidson endorsed Keynes’s liquidity preference theory of interest, and he emphasized fundamental uncertainty as a central feature of economic reality, essential to making sense of a monetary economy. His greatest legacy is the Journal of Post Keynesian Economics, the intellectual home for a generation of Post Keynesian economists. Without his efforts, the heterodox economics community would be significantly smaller than it is now.