John Maynard Keynes’s analysis of the Great Depression has strong parallels to recent theorizing about the post-2008 Great Recession. There are also remarkable similarities between the two historical episodes: the collapse of demand for new fixed investment, the role of the zero lower bound liquidity trap in hampering conventional monetary policy, the multi-year period of near-zero short-term rates, and the protracted period of subnormal prosperity. A major difference between then and now is that monetary authorities in the recent situation actively pursued an unconventional policy with massive purchases of long-term securities. Keynes couldn’t convince authorities of his era to pursue such a plan, but it was precisely the monetary policy he advocated for a depressed economy stuck at the zero lower bound of nominal interest rates.