There are 4 books in the Heroines Behind the Lines series. The newest book is Spy of Richmond which came out in 2015.

1
Wedded to War

Book cover of Wedded to War
*2013 Christy Award Finalist (Historical Fiction and First Novel categories)
It's April 1861, and the Union Army's Medical Department is a disaster, completely unprepared for the magnitude of war. A small group of New York City women, including 28-year-old Charlotte Waverly, decide to do something about it, and end up…
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3
Yankee in Atlanta

Book cover of Yankee in Atlanta
When Union soldier Caitlin McKae woke up in Atlanta wounded in battle, the Georgian doctor who treated her discovered one secret — that she was a woman disguised as a man — but he did not realize that she was Union, not Confederate. In order to avoid arrest or worse,…

4
Spy of Richmond

Book cover of Spy of Richmond

Trust none. Risk all.
Richmond, Virginia, 1863. Compelled to atone for the sins of her slaveholding father, Union loyalist Sophie Kent risks everything to help end the war from within the Confederate capital and abolish slavery forever. But she can't do it alone.
Former slave Bella Jamison sacrifices her freedom…