Early 20th century American labor and working-class history is a subfield of American social history that focuses attention on the complex lives of working people in a rapidly changing global political and economic system. Once focused closely on institutional dynamics in the workplace and electoral politics, labor history has expanded and refined its approach to include questions about the families, communities, identities, and cultures workers have developed over time. With a critical eye on the limits of liberal capitalism and democracy for workers’ welfare, labor historians explore individual and collective struggles against exclusion from opportunity, as well as accommodation to political and economic contexts defined by rapid and volatile growth and deep inequality. Particularly important are the ways that workers both defined and were defined by differences of race, gender, ethnicity, class, and place. Individual workers and organized groups of working Americans both transformed and were transformed by the main struggles of the industrial era, including conflicts over the place of former slaves and their descendants in the United States, mass immigration and migrations, technological change, new management and business models, the development of a consumer economy, the rise of a more active federal government, and the evolution of popular culture. The period between 1896 and 1945 saw a crucial transition in the labor and working-class history of the United States. At its outset, Americans were working many more hours a day than the eight for which they had fought hard in the late 19th century. On average, Americans labored fifty-four to sixty-three hours per week in dangerous working conditions (approximately 35,000 workers died in accidents annually at the turn of the century). By 1920, half of all Americans lived in growing urban neighborhoods, and for many of them chronic unemployment, poverty, and deep social divides had become a regular part of life. Workers had little power in either the Democratic or Republican party. They faced a legal system that gave them no rights at work but the right to quit, judges who took the side of employers in the labor market by issuing thousands of injunctions against even nonviolent workers’ organizing, and vigilantes and police forces that did not hesitate to repress dissent violently. The ranks of organized labor were shrinking in the years before the economy began to recover in 1897. Dreams of a more democratic alternative to wage labor and corporate-dominated capitalism had been all but destroyed. Workers struggled to find their place in an emerging consumer-oriented culture that assumed everyone ought to strive for the often unattainable, and not necessarily desirable, marks of middle-class respectability. Yet American labor emerged from World War II with the main sectors of the industrial economy organized, with greater earning potential than any previous generation of American workers, and with unprecedented power as an organized interest group that could appeal to the federal government to promote its welfare. Though American workers as a whole had made no grand challenge to the nation’s basic corporate-centered political economy in the preceding four and one-half decades, they entered the postwar world with a greater level of power, and a bigger share in the proceeds of a booming economy, than anyone could have imagined in 1896. The labor and working-class history of the United States between 1900 and 1945, then, is the story of how working-class individuals, families, and communities—members of an extremely diverse American working class—managed to carve out positions of political, economic, and cultural influence, even as they remained divided among themselves, dependent upon corporate power, and increasingly invested in a individualistic, competitive, acquisitive culture.