Communism is a political process whose most widely-accepted incarnation is credited to the Russian philosopher Karl Marx. The etymology of the word 'Communism' is suggestive of the ideals that are latent within its ideology; a communist society promotes a communal - and collective - ownership and method of production - this methodology opposes the ideals of a capitalist society.
In many cases, the process of a Communist government places a large part of the a society's value on both the needs and the abilities of its members, which allows for a direct connection between the the creation of goods, as well as their respective distribution. As opposed to a Capitalist society, the amount of property that an individual can either create or accrue is limited to their individual needs and abilities; this is one of the many Communist principles that aids in the removal of a class-system.
Although there does exist a governmental body in a Communist system, the role of this type of government exists in order to assess the individual abilities and needs of the individuals that it serves. According to the tenets of Communism, by allowing for the direct relationship between a society's members and their means of both reward - as well as production - alleviates a majority of alienation felt on the part of that particular society.