Postmodernism and History by Richard Evans
Like determinism, postmodernism -- precisely, postmodern perspectivism -- has soft and hard versions. The soft version makes the obvious claim that perspective sometimes makes some difference in our perceptions of the world. The hard version, which comes from post-structuralism, suggests that anyone's idea of truth is always and totally part of that person's social discourse, and has no more claim to the truth than anyone else's.