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.[1][2]