This document provides an overview of Marxism and class theory. It discusses how Marx viewed ideology as serving the interests of dominant social classes. The ruling classes promote ideologies that distort reality and perpetuate unfair systems. Marx defined class based on relationships in production - those who own capital versus those who must work for wages. Over time, the classes and dominant ideologies may change as economic and social conditions evolve. The document uses New Zealand as a case study, noting how classifications of social class have shifted with economic reforms over the decades.