For a century, two labor market empirical regularities characterized the movements of the hours of work, employment, and hourly compensation of American manufacturing production workers. They resembled conditional labor supply functions. Increases in employment substituted for reductions in hours per worker. The implied elasticities of hours and employment with respect to hourly earnings declined in absolute value over time. The activities of trade unions and the effects of statutory legislation contribute to the explanations for what is observed. Recently,changes in real hourly earnings contribute little to understanding movements in hours of work and in employment of these workers.