Karl Marx, the philosopher, economist, political theorist and socialist revolutionary, is best-known for the 1848 pamphlet, The Communist Manifesto and the three-volume Das Kapital. His theories, called Marxism, maintained that class conflict leads to the development of human societies and that internal tension were inherent in capitalism, which would ultimately be replaced by the socialist mode of production.
W. E. B. Du Bois was an American civil rights activist, sociologist, and Pan-Africanist. Du Bois played an instrumental role in fighting for full civil rights for people of color around the world. A co-founder of the National Association for the Advancement of Colored People, Du Bois also played an important role as the leader of the Niagara Movement.