The Condition of Postmodernity:  An Enquiry into the Origins of Cultural Change
- David Harvey

To understand postmodernism, we need to examine modernism (the ideas that postmodernism rejects):

Modernism:  (typified by thinkers of the 18th century Enlightenment era)

Postmodernism:

Meta-theories / Metanarratives:  postmodernism rejects these 'universal' human theories (for example:  Michel Foucault - 'Petit History')

The shift from modernism to postmodernism:  a paradigm shift (a somewhat postmodernist idea by Thomas Kuhn)