Union Booms and Busts takes a bird's eye view of the shifting fortunes of U.S. workers and their unions on the one hand, and employers and their organizations on the other. Using detailed data, this book analyses union density across 11 industries and 115 years, contrasting the organizing and union building successes and failures across decades. With attention to historical developments and the economic, political, and legal contexts of each period, it highlights workers' and their unions' actions, including strikes, union elections, and organizing strategies as well those of employers, who aimed to disrupt union organizing using legal maneuvers, workforce-based strategies, and race and gender divisions. By demonstrating how workers used strikes, elections, and other strategies to win power and employers used legal maneuvers, workforce-based strategies, and race and gender divisions to disrupt unions, the authors reveal data-driven truths about the ongoing history of unionization. Chapters follow time periods: the early unregulated period where unions took hold in only a handful of industries; the mid-century regulated period where strikes, elections, and union density grew across industries; and the later dis-regulated period where union trajectories diverged, with some industries seeing drastic decline and others holding steady. The book concludes by turning toward what might come next for workers and unions in America and provides access to on-line data for readers who want to take a closer look