Ritual was first published in 1988 under the title Feast. This is the British paperback edition by Sphere from 1989. I haven’t seen a physical copy of this book, but my understanding is that the image above depicts the front cover, which has a triangular window that reveals a detail from a second cover underneath. The image below shows a 1993 reprint by Warner Books which apparently uses that second cover as the primary one.
The bold eroded caps are from a typeface known as Frankenstein. The wide flare serif used for “Ritual” is ITC Newtext, which was also used for a number of other Masterton books published by Sphere. The typeface used for the author’s name is unidentified, or maybe a heavily customized American Gothic.
1993 reprint by Warner Books