Postmodernism emphasizes the role of individual, rather than standardized or canonical, reaction to and interpretation of our experiences. In art, Postmodernism, like Modernism, does not make strong distinction between low and high forms (as prior art movements had), rejects rigid genre boundaries and favors mixing of ideas, and promotes parody, irony, and playfulness. Unlike Modernism, Postmodern art does not approach this fragmentation as tragic, but rather revels and celebrates it. Modernists desired to find core underlying fundamentals of art, whereas postmodernists approach the subject from a belief that it is more fruitful to copy, emulate, and recreate past artforms in new ways than to generate new kinds of art.
In economics, Postmodernism refers to multinationalist, consumer-based capitalism, as opposed to monopoly capitalism associated with Modernism through the first half of the 20th century, or market capitalism before that. Some think that the shift in mode and technology of production may have precipitated or at least emphasized the change to Modernism and then to Postmodernism.
[Postmodernism -- In Popular Literature]?
For a light hearted introduction to Postmodernism, I recommend Douglas Adams' series Dirk Gently's Holistic Detective Agency. His better known work The Hitchhiker's Guide To the Galaxy also has many philosophical elements, including Postmodern ideas.
Postmodernism -- In Philosophy
[Postmodernism -- In Architecture]?
See also Syncreticism, Sokal Affair, New Age, Critical Theory