An Impartial Witness, by Charles Todd
The second Bess Crawford mystery is very good! It's the third one I've read, because I got them in the wrong order, but they're quite self-contained and it didn't matter at all. Bess spends more time out at the front this time, which was nice, and the mystery is intriguing but very sad. She is awfully brazen about butting into people's lives and introducing herself to useful folks, but I guess you have to do that if you're going to detect murders.
I didn't realize before that "Charles Todd" is a mother and son writing team--and they live in different states! How on earth it is possible to write a mystery that way is beyond me, but they sure do a good job. Now that I'm out of Bess Crawford stories, I'll have to give their Ian Rutledge series a try.