"Mrs Mohr Goes Missing" by Maryla Szymiczkowa (pseudonym of Jacek Dehnel and Piotr Tarczyński, who wrote it together and privately are a couple).
It's the first book in a Polish crime series, set in the late XIXth century Cracow. The main character is this conservative, respectable housewife, who loves to get herself involved in crime investigations.
The whole series is very well researched & gives you a great insight into how people lived back then, what they ate etc. It's also really funny but still has that 'horror lurking behind' vibe - lots of crime, greed and violence behind the mask of respectability and religiousness.