The Wartime Sisters by Lynda Cohen Loigman

Ruth has always been in the shadow of her beautiful younger sister, Millie. Throughout childhood, their mother always had big plans for what Millie's life would be like, but never paid attention to Ruth's accomplishments, even though she was considered quite intelligent. Now, as adults during World War II, Ruth and Millie haven't see each other in five years. When Millie's husband is killed in the war, she moves to Springfield, Massachusetts to live with Ruth and her family. Ruth's husband, Arthur, is a scientist at the Springfield Armory, and Millie ends up getting a job helping assemble weapons there. Will Ruth and Millie be able to heal the rift between them that has grown even wider over the years? The Wartime Sisters explores the sisters' lives along with those of their friends in the large Armory community.