Mid-sixties monster magazine; the indicia (page 3) says it is "Designed and produced by the House of Horror, London, for Acme News Co., Inc., 119 Fifth Avenue, New York City, New York 10003."
Edited by "Frank N. Stein" — Issue #3, cover dated Summer, 1966. Links for issues #1 and #2 below.
Copyright © 1966 Acme News Co., Inc.
SHRIEK #1 can be found here. SHRIEK #2 can be found here.