Marxism is a social theory created by Karl Marx in the 19th century. Being one of many popular social theories, this particularly focuses on the conflicts within society and the relationships between social classes.
The concepts of Marxism covers the ideas of materialism, socialism and communism. It also suggests relevent points for the ideas behind the crisis theory, exploitation, surplus value and cultural hegemony. All points that are supported by Marxists show their beliefs that societies should be communist and focus on the equality and fairness of the lives of everyone. 
Marxist views are primarily based on the critical analysis of Capitalism and the exploitation of the Proletariat from the Bourgeoisie. This methodology focuses on the economic structure within the means of production, suggesting that the Bourgeoisie benefit from the labour of the Proletariat through private profit. 
There is also the idea of an overcoming social crisis within Capitalist societies due to overproduction, as so predicted my Marx.  This then runs into the risk of further discrimination, political as well as economically, which could lead to dramatic changes of social policies within such societies. This could push the proletariat to turning to crime. Marxists percieve crime to occur due to a Capitalist economic system being a major influence between social relationships, beliefs and values.