Drawing on underexplored and only recently available archives, author Chrystyna Dail examines the influence of Stage for Action, a theatre group founded in 1943, on social activist theatre in the 1940s, early 1950s, and beyond. The group embraced subjects not taken up by earlier activist theatre companies—advocating for the rights of Puerto Ricans, calling attention to the lack of child care for working mothers, and demanding the cessation of all nuclear warfare. Exploring the intersection between performance and politics and the direct impact of the arts on social activism, Dail argues Stage for Action is a theatrical reflection of progressivism and the pro-working-class theatrical aesthetic of the 1940s. The theatre group, which used performance to encourage direct action and personal responsibility for change, eventually would function as the theatrical voice of the United States Progressive Party in the failed presidential campaign of former vice president Henry A. Wallace. Calling into question the widely held belief that US theatre in the early years of the Cold War was indifferent to activism, Stage for Action offers historians a new interpretation of social activist performance at midcentury.