"Money is a wonderful thing. It started out in human history as hard currency, generally gold or silver. These are commodities that are deemed to have intrinsic value but also act as a means of abstractly representing wealth accumulated out of other real commodities. Relatively little hard currency ever circulated freely in the preindustrial world. In that world, most wealth was actual, existing in the form of land, palaces, fleets of boats, bolts of cloth, barrels of grain, standing timber, herds of cattle, and so forth. These were generally things that could be traded, and exchanges of these items were often facilitated through the medium of gold or silver, hence the term "medium of exchange." [The] hard currency could also be acquired by theft or plunder, though that did not necessarily affect its value. Note that the value of [the] hard currency is transcultural. Gold and silver had high value to the Europeans, the Chinese of the Sung dynasty, the Inca, the Aztecs, the ancient Egyptians, and the California Forty-niners. The industrial experiment took the idea of currency (money) to the next level of abstraction—as hard currency can represent actual goods, so paper currency can represent hard currency and actual goods. As trade increased and took place over ever-greater distances, paper promises to pay hard currency began to steadily take the place of the hard stuff itself, which was cumbersome, hard to lug around in large quantities, and subject to theft in transit. So, to streamline these trades, all kinds of certificates were used as equivalents to hard currency: individual IOUs, bills of lading, letters of credit from rich people, [and] promissory notes issued by guilds. In time, the use of paper certificates became… more normative and conventionalized. Protocols of exchange were established. Institutions were created to process them. This process of managing monetary affairs—of wealth abstracted in [a] paper—was called finance."