Marxist Theory

Marxist Criticism
Marxist Criticism is, not surprisingly, concerned with economic conditions.  Marxist Critics are often interested in social class (as feminist critics are interested in gender).  They see literature as a "product"--something produced by work, (compare an auto--something produced by factory workers and engineers) sold in a marketplace.  They thus can see readers as consumers of these products.
Marxist Critics are very concerned about the structures of a society.  They see a society's economic structures as its base--the foundation on which a society rests (think, "basement").  Societies are inherently conservative, so each society (especially those in it currently benefiting from whatever economic base is in place) wants to perpetuate or continually reproduce its base--those foundational economic structures.  Those foundational economic structures are often class interactions and power hierarchies.  
It's easiest to think of this in terms of a society NOT our own--say feudal Europe ~ 1100.  The fundamental economic base would be feudalism, the economic system in which the king owns all, and grants lands to his nobles, who have their land farmed by serfs and/or granted out in turn to lesser nobles, such as knights in a chain of decreasing privilege and increasing work on the farm.  Of course, literary works produced by members of this society would either glorify (and hence reproduce) feudalism by glorifying knightly deeds and casting aspersions on ignorant peasants, or some few literary works would be "radical and countercultural" and try to undermine the feudal system in subtle ways.  Hence the proliferation of the Robin Hood legends.  I'm so oversimplifying the Middle Ages, but I hope this gives you a small idea of how literature can be out in the world doing social manipulation of its consumers.
The continual reproduction of the base is ensured in two ways by the base's superstructure.  The first and most obvious and least effective...