What is Friedrich Engles's economic theory? What is the influence of his theories?

Friedrich Engels, along with Karl Marx, was one of the fathers of socialist political and economic theory, often referred to as political economy.
In The Holy Family (1844) and more fully in The Communist Manifesto (1848), Marx and Engels laid out their explanation of capitalism as an all-encompassing system that elevated the interests of the owners, who gained wealth and accumulated capital only through exploitation of the workers. Value, they argued, was in fact created by the workers' labor. The idea that the workers would overturn the hierarchy and create a classless society is one strong lasting influence, as it was taken up in Russia's 1917 Revolution and considered the foundation for Soviet Communism.
After Marx died, Engels went on to write Origin of the Family, Private Property, and the State (1884). While expanding on the historical bases of capitalism, this work also located exploitation in the nuclear family and the dependence on unwaged female labor in the home. It later gained further influence in feminist theory.
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