Steven Kates has an interesting essay at Liberty Matters addressing what was the conventional wisdom in "macroeconomics" at the time of John Stuart Mill, how that was transformed by John Maynard Keynes, and what was the consequences as a result. In Kates's narrative, knowledge was lost and the consequences are damaging for macroeconomic policy.
He concludes his essay by stating:
We seem to have a completely false notion that economic theory moves only forward, that the latest is the best, and that past has been transcended. The reality is that the economics of Mill, even his 1848 first edition, will provide more insight into the operation of an economy than any of the Samuelson clones that have been published to explain what Keynes meant in trying to raise aggregate demand.
Commenting on Kates's essay will be Nick Capaldi, Richard Ebeling, and Sandra Peart. You can follow the conversation for the next month.