Dear Mohammad, The GT is not at all about market clearing and failures to clear (that's the New Keynesian version of Keynes's theory, which is misinterpreting the latter just as the writers of the so-called neoclassical synthesis did). I suggest that you read Keynes's 1933 papers on a monetary theory of production CWJMK, vol. XIII, pp. 408-411, and XXIX, pp. 76-106. With best wishes, Claude Gnos