While women were not permitted to serve in the military until 1901 in the Army Nurse Corp and 1908 in the Navy Nurse Corp1, that didn't stop Sarah Edmonds and many others from crashing through that glass ceiling in disguise. The first book I read along similar lines was Pam Munoz Ryan's Riding Freedom.
Nurse, Soldier, Spy: The Story of Sarah Edmonds, A Civil War Hero
Author: Marissa Moss
Illustrator: John Hendrix
Published 2011 by Abrams Books for Young Readers (oops! This was on the "New" shelf at my library but it's not so new. I loved it, so I'm still going to review it a smidgen late)
To review, I borrowed this copy from the public library. And since it's from 2011, there is little chance that I'll be having a review copy sent!