When former heavyweight champion Jim Jeffries came out of retirement on the fourth of July, 1910 to fight current black heavywight champion Jack Johnson in Reno, Nevada, he boasted that he was doing it "for the sole purpose of proving that a white man is better than a negro." Jeffries, though, was trounced. Whites everywhere rioted. The furor, Gail Bederman demonstrates, was part of two fundamental and volatile national obsessions: manhood and racial dominance.

In turn-of-the-century America, cultural ideals of manhood changed profoundly, as Victorian notions of self-restrained, moral...