One final point: history provides us with relatively few examples of societies that were technically progressive. Our own world is exceptional though not unique in this regard. Consequently, this study will necessarily draw from a small sample and be heavily biased toward Western economic history. I shall leave out the prehistoric and very early eras, and limit the discussion of the post-1914 period to a minimum. Between about 500 B.C. and 1914 there is a record so stupefyingly abundant in facts and evidence, that I can only scratch the surface of a deep and rich seam.