The Devil's Harmony is the 5th Phineas Fox historical mystery by Sarah Rayne. Due out 2nd Feb 2021 from Severn House, it's 256 pages and available in hardcover and ebook formats. It's worth noting that the ebook format has a handy interactive table of contents as well as interactive links and references throughout. I've really become enamored of ebooks with interactive formats lately.
This is a masterfully rendered historical mystery wrapped around a framework of actual historical occurrences across several timelines: 1918 Russia, WW2 Warsaw, and modern day England. The author is adept at weaving fiction and history seamlessly, it's not always clear where real history shades over into fiction. The author's characterizations are believable and three dimensional. The story is poignant and compelling.
Although it's the 5th book in the series, it works quite well as a standalone. Though occasionally characters refer to things which happened in earlier books, there aren't any major spoilers. This was my first foray into the series, and I've added the previous books to my TBR pile.
Four and a half stars. I recommend it highly, especially to fans of historical mystery featuring academic sleuths, and music/classics. Very well done.
Disclosure: I received an ARC at no cost from the author/publisher for review purposes.