In my search for information on the ACE Doubles (and Singles), I have found a useful reference for the British publications (including the ACE imprint that I was uncertain about). This reference (information sent to me by a helpful reader) is The Mushroom
Jungle: A History of Postwar Paperback Publishing by Steve
Holland (1993) which I ordered from Barnes & Noble (or from
Gary Lovis at www.gryphonbooks.com)
. It appears as if the Black Spade Logo with the ACE imprint is
separate from the ACE American editions. From a paragraph on p. 176: "The closure of Archer Press and Harborough Publications in January 1954 were not to be the last heard of romance writer Paul Renin, for in 1955 Raymond and Lilian Locker reappeared as Verlock Press with more reprints. They had already experimented with a series of reprints under the names Trident Books and Trent Books, the former including the first reprinting of the now famous Jim Thomson, the latter reprinting a series of Ace Doubles from America. Rather confusingly they became Ace Books in 1957, although there was no connection with the American company. Ace Books was sold to Four Square Books in October 1959, then owned by the Godfrey Phillips tobacco company."
H-160 JOHN STEINBECK In Dubious Battle (1958; 1st thus)
H-173 BENGI DANIELSSON Love In The South Seas (1958; 1st thus)
H-188 GERALD KERSH Night and the City (c. 1938; this edition April 1959; 1st thus)
H-193 ANDRE SOUBIRAN The Healing Oath (Harborough Publishing Co. 1958; 1st thus)