 Often, technological progress consists of innovations that lower transaction cost: steam boat, railroad, air travel, telegraph, telephone, internet, bar code reader, “apps” that make possible such businesses as Uber and AirBnB, along with innovative organizational structures and business models such as Federal Express or container ships (which, after a ten-year legal battle with trade unions, reduced from days to minutes the time that a truck’s contents would spend at the dockyard before being transferred to a ship). In many cases, the cost of transacting concerns the cost of information. As the frontier of knowledge expands, the slice that a given individual can grasp inevitably becomes a smaller fraction of the whole. Prices become an increasingly indispensable window to a world of tacit knowledge.