Tugan-Baranovsky's theory of crises has two components: a theory of markets, defining the condition under which expanded reproduction can take place, and a theory of crises proper, explaining how any rupture of equilibrium is amplified and extended to the whole system and gives rise to periodical fluctuations. The former, based on the Marxian schemes of reproduction, is logically preliminary to the latter, which relies on the accumulation and depletion of loanable funds. In spite of Tugan's insistence on this nexus, academic commentators have ignored Tugan's theory of markets, while Marxist critics have focused exclusively on this aspect and charged Tugan with upholding Say's Law. While this reading is not entirely justified, there is indeed a deep difference between Tugan's and Marx's interpretation of crises. While Marx considers crises as the necessary corrective to the systematic and necessary breaches of equilibrium, Tugan sees equilibrium as the norm and crises a deviation from it, albeit recurring and periodical.