What is postmodernism? Why is it important? What definitions other than those in the text and Study Guide can you find?

What do cultural critics have to say about it? Cite examples of postmodernism in other art forms in the discussion.
Read, view, and reference the following for your answer:
Chapters 15 and 16 in the textbook American Cinema/American Culture by John Belton, Unit 10 (“The Film School Generation”) in the Study Guide by Ed. Sikov, and view Program 9 (available here: http://www.learner.org/resources/series67.html)