Karl Marx's three-volume study Das Kapital (1867, 1885, 1894), along with the earlier Manifest der kommunistichen Partei ( The Communist Manifesto , 1848), which he co-wrote with Friedrich Engels (1820–1895), and other works, were important to the nineteenth and twentieth century's numerous class struggles and wars of national liberation. Marx (1818–1883) argued that capitalism, although responsible for technological development and some social achievements, was fundamentally defective in that it was based on profit and human exploitation. Marx believed that capitalism would necessarily become outmoded, although his writings, especially the exhortative Manifesto , expressed the conviction that communism—the public control of the means of production—would occur only through human agency, namely revolution; those who benefit from capitalism would not simply step aside and allow the system to be replaced by a system beneficial for workers, the enormous and most productive class that communism would assist. For Marx, who wanted to develop a scientific understanding of the impact of economic systems on humanity, reformism and acts of charity would do little to transform a fundamentally exploitative system such as capitalism into a more just one such as socialism.
Later Marxists such as Vladimir Lenin (1870–1924), Leon Trotsky (1879–1940), Mao Zedong (1893–1976), and Che Guevara (1928–1967) would develop programs of revolutionary action, as would numerous non-Marxists aligned with anticapitalist movements such as anarchism. After Joseph Stalin (1879–1953) established himself as dictator of the Soviet Union following Lenin's death, various Western Marxists such as Antonio Gramsci (1891–1937), György Lukács (1885–1971), Louis Althusser (1918–), Herbert Marcuse (1898–1979), Theodor Adorno (1903–1969), and Max Horkheimer (1895–1973) would rethink Marxism relative to the political issues of the twentieth century, often linking Marxism to such movements as Freudianism to bolster Marxism's radical essence and to challenge forms of social injustice beyond economic formulations of base and superstructure. By the mid-twentieth century Marxism had become connected to the defeat of racism and endorsement of gender equality and sexual liberation. Walter Benjamin (1892–1940), a member of the Frankfurt School of political and social thought, became important to film theory for his essay "The Work of Art in the Age of Mechanical Reproduction" (1935–1936), in which he argued that the "aura" of great works become diminished by the process of reproduction. Although this process had a democratizing aspect, it also tended to remove an artwork from its historical-political context. Benjamin followed a solidly Marxist argument that the artwork was very much conjoined to class assumptions.