The French Powder Mystery

US precedes. Stokes, New York 1930 is the true first; the Victor Gollancz issue, London 1930 — black cloth lettered in red, carrying the full subtitle 'A Problem in Deduction', 319 pages — is the first UK edition and is collected as such, dealers describing it as 'first UK edition' rather than the first. Ellery Queen was the joint pseudonym of the American cousins Frederic Dannay and Manfred B. Lee, and Stokes was the originating publisher. Census claim confirmed as to the true first. Month-level dating of the Gollancz was not established, but no source consulted places it ahead of the Stokes.