Jean-Francois Lyotard was a French philosopher best known for his articulation and analysis of postmodernism. In his 1979 work The Postmodern Condition: A Report on Knowledge, he introduced the concept of "metanarratives" or "grand narratives" - all-encompassing theories that claim to explain historical events and give meaning based on universal truths. Lyotard was critical of these narratives, arguing that postmodernism involves skepticism of universalizing theories. He believed knowledge had become a commodity communicated through local narratives rather than grand narratives, which postmodernism sees as inadequate.