The Origin of the Family, Private Property, and the State is an 1884 treatise by Friedrich Engels. The work is partially based on notes by Karl Marx to Lewis H. Morgan's book Ancient Society (1877) and is regarded as one of the first major works on family economics.
Engels argued that the traditional monogamous household was a recent construct, closely bound up with capitalism. He called it a patriarchal system in which women were servants and claimed that communism would herald the dawn of communal living and a new sexual freedom. The role of the state would then become superfluous.