We might ask why printers built the first union in California. The answer is that members of this occupation were literate, had deep roots in guild traditions, and were already doing similar things around the country. The enthusiasm for public education in the early republic created a readership for newspapers, books, and printed materials of all kinds. The spread of literacy meant growing markets for the printed word and jobs for printers. But the industrial revolution, urban competition, and advances in printing technology put steady pressure on the craft of printing. Printing had been based on hand-run printing presses, and on guilds, in which masters taught apprentices and journeymen and all shared age-old cultural traditions and expectations.