This was the book that caused me to expand my horizons, from a long-established steady diet of science fiction and fantasy, to include mysteries. My best friend STOLE IT from a rack of paperbacks at the grotty little store off campus and gave it to me for my 18th birthday. (I didn't know until much later that she had stolen it.)
Beginning in 1944 with The Case of the Gilded Fly
and ending with the publication of Glimpses
shortly before his death in 1978, Crispin (aka Bruce Montgomery) produced nine novels and two collections of short stories, the bulk of which star his urbane detective, Gervase Fen. In between he also edited SF anthologies, wrote both classical music and film scores, and drank a good deal, which apparently was a major cause of his early death.
The cast of Glimpses
far outpaces the rest of his work in terms of sheer absurdity (among them a vicar who punctuates his conversation with snippets of commercial jingles, fox hunting eccentrics, and the disembodied head of the murder victim, which pops up in unlikely situations through the course of the book) and I suppose this is not his best writing, but it's still my favorite, because it was my first.