"The Sword of Antietam" is part of the Civil War series by Joseph Altsheler It was published in 1914. Altsheler was a prolific writer of youth fiction. He did series of books on the French and Indian War, Great West, Young Trailers, Civil War, World War, and Texas. The Sword of Antietam is part of the Civil War series.
The book is what you would expect from a book for teenagers written in 1914. The prose is workmanlike and a bit repetitive. The soldiers talk floridly which was probably fairly authentic, but still cringe-inducing. The main character is Dick Mason, a Yankee soldier from Kentucky. He is an officer in Winchester's Regiment. Being an officer, he is not only in the thick of the fighting, but also privy to some of the strategic discussions of command. He is also too good to be true, as you might expect. So are his friends.
The book is pretty accurate and a teenager can learn a lot about the Civil War in 1862 from it. Altsheler obviously has done his research. He even includes the entire text of Lee's famous "Lost Order". The book covers Second Bull Run, Antietam, Perryville, and Murfreesboro. You do get a feel for the movements of the armies. The combat is not graphic, but you do get the impression that they were very bloody. You also get a clear picture of tactics.
The main drawback of the book is it gives you the feeling that the Civil War was an incredibly small world. There are thousands of men involved, yet there are some incredible coincidences and contacts. Dick finds a wounded friend's body at night in a corpse-covered field within minutes with the help of a Rebel who he had met earlier on picket duty! Dick meets his BFF who is now in the Rebel army a couple of times during the campaign. Guess who finds the "Lost Order"? Dick's mother shows up to help find his injured body at a later battle! Men are getting killed in seemingly suicidal frontal charges into the mouths of cannons and volly fire and yet none of the main characters gets killed. Realism is not a strength of this book.