The article explores how effective demand, money, credit, and finance are interconnected in economic theories by Marx, Kalecki, Keynes, and the monetary circuit school. It delves into the relationship between endogenous credit, finance, investment, and saving to clarify any confusion in post-Keynesian economics. Marx's views on money, effective demand, and capital accumulation are also discussed, showing how Kalecki was influenced by Marx's approach. The researchers use Schumpeter's distinction between 'monetary analysis' and 'real analysis' to analyze these theories as 'monetary analysis'.