A. J. Muste is best known for his involvement in the left-wing and labor struggles of the 1920s and 1930s and for being the titular head of the American peace movement. Muste's historical significance goes beyond his leadership of organized movements for peace and economic justice, however. He played a central role in making the principles of nonviolence established by Mohandas Gandhi a permanent feature of American political culture in the post-World War II era. As a Christian, he offered a model of Christian vocation and faith that challenged the rise of Christian realism (also known as neo-orthodoxy) popularized by Reinhold Niebuhr and that in many ways served as a precursor to liberation theology. As a lifelong radical, his life and politics challenge the narrative of 1930s radical turned Cold War liberal that has dominated historical understanding of the twentieth-century Left. As a social critic, Muste combined keen...