In the novel, Sergeant Timothy Chase uses his eyewitness experience of the Monitor and Merrimack battle of 1862 as an entertaining dramatic narrative to deflect the anger some other federal troops occasionally turned on him and his comrades of the 29th Massachusetts Infantry Regiment.

They would do so, from time to time, because Massachusetts was widely known as a hotbed of abolitionism and even in late 1863, months after President Lincoln’s Emancipation Proclamation, freeing the slaves was still controversial in the North. White men there still  volunteered to fight, not for black freedom, but for the preservation of the Union—one nation, indivisible.

Civil War historian Gary Gallagher’s new book The Union War helps modern readers understand this lately-discarded fact of the war’s history and how emancipation, now often said to have been paramount from the war’s beginning, was, in fact, late in capturing the dedication of the North and its white citizen-soldiers.

Which is probably part of the reason the war was followed by almost a hundred years of racial segregation—in the North as well as in the South.