Post-Keynesian economics is a school of economic thought with its origins in The General Theory of John Maynard Keynes, with subsequent development influenced to a large degree by Michał Kalecki, Joan Robinson, Nicholas Kaldor, Paul Davidson, Piero Sraffa and Jan Kregel. Historian Robert Skidelsky argues that the post-Keynesian school has remained closest to the spirit of Keynes' original work.
The term post-Keynesian was first used to refer to a distinct school of economic thought by Eichner and Kregel (1975) and by the establishment of the Journal of Post Keynesian Economics in 1978. Prior to 1975, and occasionally in more recent work, post-Keynesian could simply mean economics carried out after 1936, the date of Keynes's General Theory.
Post-Keynesian economists are united in maintaining that Keynes' theory is seriously misrepresented by the two other principal Keynesian schools: neo-Keynesian economics, which was orthodox in the 1950s and 60s, and new Keynesian economics, which together with various strands of neoclassical economics has been dominant in mainstream macroeconomics since the 1980s. Post-Keynesian economics can be seen as an attempt to rebuild economic theory in the light of Keynes' ideas and insights. However, even in the early years, post-Keynesians such as Joan Robinson sought to distance themselves from Keynes and much current post-Keynesian thought cannot be found in Keynes. Some post-Keynesians took a more progressive view than Keynes himself, with greater emphases on worker-friendly policies and redistribution. Robinson, Paul Davidson and Hyman Minsky emphasized the effects on the economy of practical differences between different types of investments, in contrast to Keynes' more abstract treatment.