The fundamental principle of Socialist/Communist Economics is not that free markets are inherently self-destructive. Socialist economics suggests that (specifically) the capitalist form of free markets contain their own self-destruction. Under socialism the economy must be controlled by a socialist market mechanism where the differentia specifica is the absence of capitalist profits (ie that above normal profits). The main difference between socialism and communism is that of degree, communism promoting more social control than socialism. The underlying tenant of Socialist/Communist Economics is not government control, but a specific concept of "associated labour" derived mainly from Marxist theory but with some Christian socialist influences.
The founding document of Socialist Economics is Karl Marx's famous "Capital" which is reflected, in practical terms, in the "Communist Manifesto" section 2. Its capitalist counterpart is Adam Smith's "The Wealth of Nations". While Smith claims that the self interest of the butcher and the baker are sufficient to balance any economy, Marx proposes that any exploitation of value from any or all parties, and used to construct capitalist profits, will eventually bring the system down. "The Communist Manifesto" is also a political book since in necessarily opposing all political forms of economic exploitation, the first stage has been conceived of as a task for some form of popular government. Consequently politics are inherent to this economic theory.