Ared White started his impressive string of short stories, novelettes, and novellas in the last months of 1926, continuing until just before the start of WWII. During that time he was busy organizing the National Guard in Oregon and attending the Army's War College and receiving lengthy training at the Command and General Staff School. And getting promoted to Major General.
The range of his subject matter shows an interest in the Napoleonic Era as well as the Great War but it was the intense concern he had with the increasing threat from the new Fascist movement taking place in Europe and a reviving Germany that dominated his writing.
The need for and the danger from espionage was his focal point for much of his output. He dallied with solo adventures of this character or that, and may have had a recurring operative for Napoleon (I have not proven it one way or the other) but once he created Captain Fox Elton, he would be drawn back to that man on many occasions.
Most of the adventures for this intrepid hero were published, fittingly, in the pages of Adventure, presented by the Ridgway company, a subsidiary of the Butterick Publishing Company. This American pulp magazine was primarily designed for male readership with tales of derring-do and thrilling escapades in a wide variety of genres and could boast stories from most of the soon-to-be giants of the industry like H. Rider Haggard, Talbot Mundy, Harold Lamb, Baroness Orczy, and Rafael Sabatini.
We know from having found copies of them that there were at least a dozen missions about Elton published, most in Adventure but several towards the end of his recorded career in Argosy.
Two of those were serialized in the magazine first but then were bound in hardback; they are mentioned above in the Book section. The other ten certain tales are detailed below.
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There are an additional four three two that I strongly suspect to be Elton tales but have not proven it. They are:
The Cipher Trail, a short story in Adventure, September 15, 1929.
Spy Nest, a novella in Complete Stories, December 2, 1929.
The Prussian Spymaster, a novella in Adventure, June 15, 1930.
The Parachute Courier, a short story in Adventure, October 1933
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There were an additional five four tales published in Argosy and Adventure over the next three years which may or may not be Elton stories. By title they are obviously spy stories but the author had crafted one story (shown as #8.5 below) in the same 'universe' but which had a different operative than Elton so it is possible all/some/none of these do as well.
The Spy At Charleville, a novella in Argosy, July 21, 1934.
Spy Cargo, a novelette in Adventure, July 1, 1935.
Spy Master, a novelette in Adventure, September 1, 1935
Parachute Spy, a novelette in Adventure, January 1936.
Dungeon of Spies, a novelette in Argosy, May 23, 1936.