Rivers of London: Body Work - Ben Aaronovitch, Luis Lobo-Guerrero, Lee Sullivan Hill, Andrew Cartmel
London Constable Peter Grant discovers something a little unusual while investigating a series of murders: he can see ghosts. Before long, he finds himself apprenticed to Investigator Nightingale ... a wizard. Because he can also do low-level magic.

Think Harry Potter meets Sherlock Holmes, and you've got it.

The title is based on the spirits associated with London's various rivers: Mother and Father Thames, Beverly Brook, Tyburn, Fleet, Oxley and more become actual people whom we meet in the course of the investigation.

The premise is clever, the "whodunnit" took me completely by surprise -- and the clever use of London's theatrical history as a basis for the plot was simply delightful. I'll look forward to reading more of these books.