"The Mapping of Love and Death" by Jacqueline Winspear
If you are a Maisie Dobbs fan, this mystery, the 6th in the series, is simply splendid. I'm not going to give you any more information about the story and ruin it for you. Just enjoy, take your time and savor the story.
If you've never read the "Maisie Dobbs" series, start with the first book. It's a gentle, well written mystery that begins before World War I in England. Each book is so satisfying that you'll crave a cup of tea and more of Maisie's story.