To most Americans, Malcolm X and Martin Luther King Jr. represent contrasting ideals: self-defense vs. nonvoilence, black power vs. civil rights, the sword vs. the shield. The struggle for black freedom is wrought with the same contrasts. While nonviolent direct action is remembered as an unassailable part of American democracy, the movement's militancy is either vilified or erased outright. In The Sword and the Shield, Peniel E. Joseph upends these...