D and Z in ROPE: Will the real Keynes please stand up?

The Review of Political Economy (ROPE) welcomed the year 2009 with an issue in which the first two articles use an interesting yet not very popular modeling framework, namely the aggregate demand/aggregate supply (D/Z) model from Chapter 3 of Keynes's General Theory. Unfortunately, as I intend to show in this paper, the interpretations of Keynes's D/Zmodel proposed by these two articles contradict each other. To resolve this unsatisfactory state of affairs, I will offer an evaluation of which of the two interpretations is more in line with Keynes's own suggestions.