What are the concepts of base structure and superstructure that Eagleton uses in Literary Theory: An Introduction, and what is literature illustrating these concepts from novels or films?
"Base structure" and "superstructure" are terms used in Marxist literary theory to describe the economic-political-cultural orientation of a society as it is reflected in a work of literature or in a collected body of literary works.
Base structure is the underlying economic framework of a society. Thomas Hardy is good at revealing the underlying economic framework of 18th century England, especially in Tess of the d'Urbervilles. The base structure for England is shown to be one in which the monied landowners dominate the labor of the unmonied land leasors who labor for their daily bread and a roof over their heads. Nonetheless, Hardy also shows the benevolent side of these economic transactions revealing a duality in the application of the base structure that exists because of the varying psychological characteristics of each landowner.
Superstructure is the religious, political, artistic and philosophical belief systems that arise out of the base structure and work to help keep the base structure stable and in power. In other words, dissent to the base structure through religious protest, through political reform, through artistic exposé or through philosophical explication must be prohibited and squelched when it arises or the dissent will topple the economic base structure and institute a different base structure.
Dickens provides a very good examination into how dissent-driven subversion of the base structure can happen through philosophical explication of the natural order of the world in A Tale of Two Cities, which shows the outcome of works like those of Voltaire and Rousseau as the actualization of events in the French Revolution. A film that shows the social effects of England's superstructure is Master and Commander: The Far Side of the World. In it, you can see the un-privileged, un-voiced Captain's Cabin servants and the privileged, voiced officers. You can see the dominance derived from the superstructure (founded upon the economic base structure) of even a 10-year old boy officer over grown un-privileged men.