For a time Bloch was everywhere. Hitchcock's Psycho had made him a household name even in Germany. When Luther Publishing started its horror paperback program, sold only at the newsstands, they put his name quite a few times on the cover.
Schrecken in der Nacht may be Terror in the Night from 1956, published first in Manhunt. Luther didn't believe in listing the original titles. Or the years of publishing. Understandable, as in the forward looking 70s nobody wanted to read 30 or 40 years old material. At least not deliberately.
Ein wirklich schlechter Freund may be The Real Bad Friend from 1957, published first in Mike Shayne's Mystery Magazine.
Die Perlenkette may be String of Pearls from 1956, published first in The Saint Detective Magazine.
Luther's Grusel Magazin was a monthly paperback, its content was like a magazine. Short stories, a few macabre cartoons, the odd article, (not very good) serialized comic adaptions of Frankenstein and Dracula. Unfortunatly the material was mainly from Singer Features, which was a bit low rent.
Content was all over the place. Stories from Weird Tales were followed by material from Manhunt or even more obscure magazines. Luther used often horror movie stills for covers, in the later years often from exploitation movies. Needless to say that the content couldn't live up to the promise.
These books are mostly forgotten today. In hindsight the content was not all bad, it introduced writers like Derleth or Seabury Quinn, did the occasional Lovecraft. Unfortunatly it did it without any context. And genuine horror stories alongside third rate crime stories wasn't a good mix. On the other hand, I can't imagine that the target audience would have cared a lot. Things like Weird Tales was an obscure information for a handful scholary types and not a selling argument.
I am pretty sure the cover of the first one is a still from the (reportedly dreadful) Ferdy Mayne film, Gebissen wird nur nachts, commonly known as The Vampire Happening in English language markets. I've never seen it though it is, or was, on you tube and I think I may have started it once. I've always said I would watch Ferdy Mayne in anything but this one could be a challenge to get through.