"Light Thickens" by Ngaio Marsh - the 32nd and final book in the "Inspector Alleyn" series. During a performance of "Macbeth" at the Dolphin Theatre is London, an actor is brutally murdered. Alleyn has to find out whodunnit. This is a superb exit to the series: well-written, engaging characters, and an ingenious murder. It's a loose sequel to the earlier book "Death at the Dolphin" (written and set 16 years earlier) and features a number of the same characters.
I'm sad to have reached the end of this series, which I've read (interspersed with other books) over the last 18 months or so. It feels like saying goodbye to an old friend, to know that I'll never again read a new "Alleyn" story
. There is actually a book of short stories that I've not yet read yet, so I think I'll save that for a future date.