Sadly this is the 4th and last book of the Starbuck Chronicles. I have thoroughly enjoyed reading the entire series, wish there were more. The series starts off in Bk 1 with the Battle of First Mannasses, and ends up in this one with the Battle of Sharpsburg (Antietam). It is a historical fiction because it uses fictitious characters to tell accurate history.
Nathaniel Starbuck is a northerner who roomed with a rich Virginian, Adam Falconer, in college and has sympathy for the South. When the WBTS starts he is in Virginia and joins his friends father's Legion in fighting for the South. To keep the non historians interested Cornwell has injected the books with spies, camp followers, murder, love, paid lovers, pompous simpletons, and a writing style second to none. I have recommended the series to many, and now I'm recommending it to you.