Basic model of income determination and extension from a simple closed economy to a four-sector economy with the derivation of the multipliers. Detailed theories of consumption (KIH, RIH, PIH & LCH) and investment (Accelerator theories, MEC, MEI, Profit Theory, Profit & Residual, Cash Flow and many others), (including under conditions of uncertainly) of the classical, Neo-Classical, Keynesian and Post-Keynesian economists; and the relevance of the theories to emerging and developing countries. The advanced treatment of the IS-LM framework within the context of government monetary and fiscal policies and in relation to output, employment, prices and inflation.