(With thanks to Didier Poiret)
After Edgard Wallace, and second perhaps only to Simenon, Peter Cheyney (1896-1951) was the great writer businessman of his age. The blurb below gives an example of how he was advertised in France at the height of his fame.
(Click to enlarge)
Peter Cheyney. Duel dans l’ombre [Dark duet..], adaptated by Michel Arnaud, Paris, les Presses de la Cité, 1950, Un mystère, 72