The Situationist International (SI) was an international organization of social revolutionaries made up of avant-garde artists, intellectuals, and political theorists, prominent in Europe from its formation in 1957 to its dissolution in 1972.
The intellectual foundations of the Situationist International were derived primarily from anti-authoritarian Marxism and the avant-garde art movements of the early 20th century, particularly Dada and Surrealism. Overall, situationist theory represented an attempt to synthesize this diverse field of theoretical disciplines into a modern and comprehensive critique of mid-20th century advanced capitalism. The situationists recognized that capitalism had changed since Marx's formative writings, but maintained that his analysis of the capitalist mode of production remained fundamentally correct; they rearticulated and expanded upon several classical Marxist concepts, such as his theory of alienation. In their expanded interpretation of Marxist theory, the situationists asserted that the misery of social alienation and commodity fetishism were no longer limited to the fundamental components of capitalist society, but had now in advanced capitalism spread themselves to every aspect of life and culture. They rejected the idea that advanced capitalism's apparent successes—such as technological advancement, increased income, and increased leisure—could ever outweigh the social dysfunction and degradation of everyday life that it simultaneously inflicted.