Young Heroes of History is a series of books that focuses on one family and how they are affected by the Civil War. Each book deals with a different family member and sometimes they bring in friends of the family. (As in Book 7 where we read about a free black who has joined the army.)
Each story is self-contained, with a specific plot, characters and climax that make it an exciting adventure all on its own. All in all, it is a series that ties in so well that the reader will easily see how one book is related to another.
Even if they only read one book, they will have a better understanding of what is going on because the background behind the characters helps fuel everything that is done.