"The unconventional monetary policy measures adopted by the major central banks in the period since 2008 are discussed in this paper. We highlight some important differences between quantitative easing and conventional monetary policy and then evaluate the mechanisms through which quantitative easing may propagate to financial markets and the real economy, drawing on perspectives from monetarist and New Keynesian theory. Additional measures, intended to supplement or strengthen the effects of pure quantitative easing, often termed unconventional unconventional monetary policy, are also assessed. In our discussion we relate the various articles in this issue to some of the key research questions posed in relation to unconventional monetary policy."

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