I have stood by their side in the grim conflict," wrote Union Captain John Chamberlin of the Corps d'Afrique. "Woe to the nation that long withholds their rights from them." Chamberlin spent nearly five years in the South during and after the Civil War. A well read, observant and articulate writer, he recorded his unique perspective as a commander of black soldiers and engineers. More than everyday accounts of camp life and battles, Chamberlin's letters and diaries --here presented in historical context--give an insider's view of the Union army's relationship with black troops and of the...