Bryan D. Palmer’s award-winning study of James P. Cannon’s early years (1890-1928) details how the life of a Wobbly hobo agitator gave way to leadership in the emerging communist underground of the 1919 era. This historical drama unfolds alongside the life experiences of a native son of United States radicalism, the narrative moving from Rosedale, Kansas to Chicago, New York, and Moscow. Written with panache, Palmer’s richly detailed book situates American communism’s formative decade of the 1920s in the dynamics of a specific political and economic context. Our understanding of the indigenous currents of the American revolutionary left is widened, just as appreciation of the complex nature of its interaction with international forces is deepened.