Pathbreaking research reveals how unions effected lasting change in some of the most far-reaching struggles of modern times. First, dockworkers in each city drew on longstanding radical traditions to promote racial equality. Second, they persevered when a new technology–container ships–sent a shockwave of layoffs through the industry. Finally, their commitment to black internationalism and leftist politics sparked transnational work stoppages to protest apartheid and authoritarianism.