Socio-Economic Formation, a historically evolved society developing on the basis of a definite mode of production; a historically determined mode of production with a corresponding superstructure. The concept of socio-economic formation first formulated by Marx is the foundation of the materialist understanding of history. It makes it possible to regard the development of human society as a regular process of the replacement of one socio-economic formation by another, more progressive one, to realise the inevitability of the transition of mankind from capitalism to communism. Historically there are five socio-economic formations: the primitive communal, slaveowning, feudal, capitalist and communist. Every one of these formations is based on a definite mode or production presenting the unity of productive forces and relations of production. The totality of the relations of production forms the economic base of the formation representing the social relations which evolve between people in the process of production, exchange, distribution and consumption of material wealth. The economic base in the final analysis determines the political and juridical superstructure, the forms of social consciousness, ideological relations, the social structure of society, the family, everyday life, etc. The appearance and development of every socioeconomic formation is subordinated to 334 specific and general economic laws which are closely inter-related. The specific laws operate at a certain stage of economic development, and determine it right up to the transition to a new stage. The general economic laws bind the socio-economic formations into a single process of development of mankind. The law of correspondence of relations of production to the nature and level of development of the productive forces is a law common for all socio-economic formations. Every formation passes through its own stages of development. For instance, pre-monopoly capitalism moves to the imperialist stage. A conflict arises at a certain stage of development of the antagonistic formation between the productive forces and the relations of production. This demands replacing the old mode of production by a new and more progressive mode. In the antagonistic socio-economic formations, based on private ownership of the means of production, the new mode of production is established as a result of the class struggle and social revolution, led by the advanced class of the time. Capitalism is the last antagonistic formation based on the exploitation of man by man. "The prehistory of human society... closes with this social formation" (K. Marx, A Contribution to the Critique of Political Economy, p. 22). The victory of the socialist revolution and the building of socialism radically change the character of historical development and open up a new era—the epoch of the transition of humanity from capitalism to communism. The communist formation has two phases of development—socialism and communism. And in turn, in its movement to communism socialist society passes through two stages: socialism which has been built in the main, and developed socialism. In the USSR, developed socialism has now been built and this has opened up broad horizons for the operation of the economic laws of socialism; the material and technical base of communism is being created, socialist relations of production are being perfected, and the differences between classes, between rural and urban life, and between physical and mental labour are being eliminated. A developed socialist society is being successfully built in several of the other countries of the socialist community.