Leslie Cargill is an author whose background is a mystery to us, if you can help in any way then please do get in touch.
None of the author's books were published in America, according ot the Library of Congress, except for Matrimony Most Murderous
I should love to see a full set of Leslie Cargill's books in dust jacket as they all will have superb period artwork.
They are, obviously, scarce in dustwrapper and collectable.
Readers will struggle as I don't believe there were any later paperback editions nor many hardback reprints.
Biography Update with thanks to Steve Cargill - I hand you over now . . .
Leslie Cargill (1895-1964) was born Leslie Clarke, but eventually took the surname of his Step Father (Cargill) and was married to my Grandmother Agnes Cargill (Known to everyone as Nessie), but I never knew her because she died before I was born.
He spent years working on the Leicester Mercury newspaper (in Leicester of course), and the 'family story' is that he was the literary editor, but I don't know for certain that he was ACTUALLY the literary editor, or whether that was just a title bestowed upon him by the family.
Editor or not though, he was definitely involved in the literary department of the paper, since even my Mother, has told of times when well known, even properly 'famous' actors., actresses, and other people connected with various sections of ' the arts' would be entertained by Leslie at his home in Kirby Muxlow (then only a village, but now a rather larger area of greater Leicester), which seemed to be his preferred venue for conducting interviews etc.
At some point he moved north up to Barrow in Furness in Cumbria, where he again worked on a local newspaper (not sure which), but in what capacity I am unsure.
He wrote 21 books in his lifetime, only one of which (The Yellow Phantom) I have actually read (not really my type of book).
You have one book missing from your list, 'The Dead Are So Dumb' (1950)
I do know that he spoke fluent German, and that his German was at such a level that he could actually pass of as a German in some of their localised dialects/accents, and a number of his books were based on spying/behind the lines Germany in or around the second world war.
He walked with a pronounced limp, the family 'story' being that he was blown up on a train in Germany, but I have no idea whether THAT is true, or just family hearsay.
Leslie had three children, my Father Michael Ian Cargill (Known to everyone as Ian - never Michael), my Uncle Eric Cargill (married to Aunt Marjorie), who emigrated before I was born and served in the Royal Canadian Air force, and my Aunt Anne (Married to Uncle Ken), who also emigrated when I was about five or six years old (to Australia) during the years of 'Assisted Passage' when Australia was still trying to recruit skilled people from Great Britain.
I think that the reason that many of his books are now to be found in either the US or in Australia is probably linked to the emigration of his siblings to those countries.
I'm not sure as to the division of importance between the work for various newspapers and/or his being a published Author worked out in terms of its contribution to his income, so I don't really know whether he was a newspaper man who wrote books on the side, or an Author who supplemented his income by working for newspapers, but I do know that neither made him a rich man.
I only ever met Leslie a couple of times, after he had moved north to Barrow, and he died when I was five.
When he died he left a three wheeled yellow sports car to my dad, but my mum wouldn't let him have it because she considered it too dangerous (being a sports car), so instead thay had to sell it (I think it might have ended up with Uncle Eric somehow), but curiously the car was known to everyone as 'The Yellow Phantom', which was also the tile of one of his books.
I'm afraid that the above is pretty much all I know about him, so I hope that it proves to be of some use to you in some way or another.
I would of course be eternally grateful for any further information that you might eventually turn up on my Grand Father if you decide to research him any further.