Cover image not available
This collection originally published, New York: Walker, 1971.
OBNB doesn't sell books, but you may be able to find a copy at one of these websites:
Horrors unknown : newly discovered masterpieces by great names in fantastic terror by Sam Moskowitz. ISBN 0718209133. Published by Kaye and Ward in 1972. Publication and catalogue information, links to buy online and reader comments.