The dynamic character of American industrialization produced imbalances between the supply of and demand for labor across cities and regions. This book describes how employers and job-seekers responded to these imbalances to create networks of labor market communication and assistance capable of mobilizing the massive redistribution of population that was essential to maintain the rapid pace of the nation's economic growth between the Civil War and World War I. It combines a detailed description of the emerging labor market institutions with a careful analysis of a variety of quantitative evidence to assess the broader economic implications for geographic wage convergence and for American economic growth. Despite an expansion in the geographic scope of labor markets at this time, the evidence suggests that labor market institutions reinforced regional divisions within the United States and left a lasting impact on the evolution of many other aspects of the employment relationship.