Looking for the roots of economic fluctuations: a formal exploration of 'Classic' and 'Keynesian' endogenous business cycles.

Can we still consider real crises and downturns as the effect of exogenous shocks? We are strongly persuaded that, in order to have a better understanding of the behaviour of the economy as a whole, the idea of capitalism as a self-sustained balanced system should be abandoned. This work addresses two main tasks. First, it attempts to retrace the seminal contributions on endogenous business cycle theory, devoting particular attention to Keynesian and Classical/Marxian models. Second, we develop a model able to encompass, at the same time, Keynesian and Marxian drivers of fluctuations. What we obtain is an important interpretive puzzle