1983 omnibus edition
I loved this collection.
The setting is an alternate Earth with magic and a long-standing English/French empire, anddespite the story years being the late 1960s/1970s, the overall technology level is Victorian (trains, revolvers, gaslights, but horse-drawn carriages).
What really makes me happy is that magic isn’t a spoiler. These aren’t tales of a detective solving a mystery merely by waving a magic wand, magic essentially replaces science in the field of forensics.
If you can find this collection (or the 2002 edition which includes 2 stories not in the version I’ve found) read it with all do haste, especially if you have a fondness for weird Victoriana.
(I haven’t read the two Lord Darcy novels written by Michael Kurland after Garrett’s passing but I do plan on keeping my eyes open for them.)