Marxist literary criticism applies the social, political, and economic theories of Karl Marx to literary texts. Some other schools of literary criticism, such as cultural studies and new historicism have been strongly influenced by Marxist ideas as well, and thus can be seen as types of Marxist criticism.
All Marxist criticism investigate the way economics, and especially class conflicts, affect literary texts. One Marxist approach looks for evidence of class struggles or economic issues within texts. Another Marxist approach is to look at how ideology and class affect authors, and thus influence how they write.
A major and growing Marxist approach to literary studies looks at the economics of authorship and book production, and how economic and class factors affect what is published, the material nature of texts, and how texts are received.