Martha Hall Kelly’s million-copy bestseller Lilac Girls introduced readers to Caroline Ferriday. Now, in Sunflower Sisters, Kelly tells the story of Ferriday’s ancestor Georgeanna Woolsey, a Union nurse during the Civil War whose calling leads her to cross paths with Jemma, a young enslaved girl who is sold off and conscripted into the army, and Anne-May Wilson, a Southern plantation mistress whose husband enlists. “An exquisite tapestry of...