Karl Marx, a 19th century German sociologist who developed the political and economic theory of Marxism, which explores the struggle of the classes and the effect in plays on society. This is one important men, as his work is directly responsible for the spread of socialism and communism, and influenced such figures as Vladimir Lenin and Mao Tsetung, who are responsible for the Soviet Union and People’s Republic of China, respectively. When you consider just how much those two states alone shaped the 20th and 21st centuries, Marx’s importance begins to be obvious.
Without Marx, we may never have landed on the moon in 1969 from a transitive point of view: No Marx > no Lenin > no Soviet Union > no Space Race. Not to mention how different the 20th century could have turned out, and how the face of the Earth might be permanently different today had Marx’s ideas never existed.
Antonio Gramsci is an Italian 20th century philosopher and sociologist.
He was the main theorist of hegemony. Hegemony is the pervasive set of ideas and ideals that come from culture and all the things we do voluntarily because we think we are supposed to. It defines what Gramsci called civil society which is basically everything which doesn’t have the threat of force behind it. (Threat of force = political society) Hegemony makes certain ideas unthinkable and other ideas unquestionable. But Gramsci also said all of us could be “organic intellectuals” and reshape hegemony and so change what is unthinkable and what is unquestionable.
The “war of position” was Gramsci’s phrase for the early part of a revolution (or “passive revolution” which was Gramsci’s idea that you could have a revolution without having a revolution by reshaping hegemony) where organic intellectuals try to get into places of influence or positions where they have a platform to better reshape hegemony.
He also spent a long time locked up by Mussolini as leader of the Italian Communist Party. There he wrote several volumes of notebooks on many topics. These notebooks took some time to be published and translated. Partial translations would be a strong influence on the Eurocommunist movement. Since then we have a fuller picture of his works and it is a bit more Leninist than it seemed at first. His writings are fairly relevant to the task of organizing and taking power in advanced capitalist societies.
Gramsci writings would influence a lot of other Marxists looking at culture, hegemony and the state. In Europe Syriza and Podemos are both heavily influenced by Gramsci and later writers building on his work such as Poulantzas with Syriza and Laclau with Podemos. Gramsci is really useful if you want to look at education and its role in class formation and such. The fact that almost every WEA (Workers Education Association) sooner or later turned from “working class culture/education” to a bland “citizens’ culture/education” can be explained using his thoughts on hegemony with remarkable clarity and ease.