Postmodernism developed after World War 2 across various fields like philosophy, art, and architecture. It rejects the notion of absolute truth and morality, instead affirming relativism. Some influential postmodernist thinkers include Jean Baudrillard who discussed concepts like hyperreality and simulacra, and Jean-Francois Lyotard who argued that we live in a world with more information and less meaning. Lyotard also discussed the rejection of "meta-narratives" and their influence on feminism in his book "The Postmodern Condition."