This is a collection of Fritz Leiber stories publsihed in 1947. It was his first collection published when he was 37. Most of the stories were written in 41 or 42 and came out in Weird Tales. The last two are Sunken Land and Adept's Gambit, well known to any Ffahrd and Grey Mouser fans. The first 7 are urban horror and really quite modern in outlook. Apart from a few details they could have been written last year. There is also a transitional story that bridges the gap between the two periods. All told it's really rather fun and shows Leiber's early promise.
This is also the title of a Dr Who Companion Chronicle and a forthcoming GUMSHOE setting written by princeofcairo. It's a quote from MacBeth, III.2: "Good things of day begin to droop and drowse, Whiles night's black agents to their preys do rouse."