The Golden Gizmo x 4

1954 Lion paperback original

a truly dreadful pulp illustration by Robert J. Lee

better image than previously posted

1989 Mysterious Press reissue

1998 Black Lizard/Vintage Crime reissue

2012 Hachette audio cover

1960 Crest reissue – cover art by Charles Binger

originally published as Duo: The Girl with a Secret and Incident at a Corner, 1959 hardcover by Coward McCann, this the later 1960 Crest paperback of just one of the novellas

cover art by Charles Binger

better image than previously posted