A union’s power rests on its ability to determine who is trained. Modern labor unions date back more than a thousand years to master craftsmen’s guilds, a kind of mutual aid society. They kept standards as well as wages high by restricting the number of people who could enter a given profession. Such alliances existed all over the world: hunters’ guilds in West Africa, merchants’ guilds in ancient India, blacksmiths’ guilds in feudal Japan.
