No signature or credit for cover art - I think the building spire looks like how Valigursky paints metal objects (like spaceships.) 1966 British title for this book was: The Creeping Shroud.

Ace (F-347) 1967 paperback. Cover by Ed Valigursky (?), frontispiece by Jack Gaughan; 159 pages. Condition is near-Fine : very tight and almost square with flat spine; age tanning is mild and uniform (about average for it age), insides of covers are much darker. No stamps, marks or writing - a clean copy with a trace of rubbing wear overall / edges still have some sharpness.