The Keynesian school, which emerged in 1930, is associated with the English economist John Maynard Keynes (1883-1946), whose most famous work is "The General Theory of Employment, Interest and Money" (1936).Keynesian analysis is an extension of the liberal current, but it challenges certain principles of classical and neo-classical analysis, which consider that the capitalist system is always stable under different economic regimes. Keynes placed his reasoning in a dynamic macro-economic framework, influenced by the scourge of unemployment in England, and demonstrated that the role of the state is fundamental in regulating the economic system in the event of a crisis.