Fin Corveth's friend Nick is robbed, and an emerald locket is stolen. Murder soon follows, and the only clue to motive is a folded piece of blank paper. Dark clouds are gathering and threaten to envelope Nick's young ward, Mariula. Fin brings in mystery writer Amos Lee Mappin, as it becomes clear that greater events are afoot than simple murder. The Mystery of the Folded Paper was published in 1930.

Jules Gartrey, a prominent banker, is killed in his apartment and the police have Al Yohe in their sights. Crime writer and occasional detective Amos Lee Mappin finds himself corralled into investigating by his staff and Yohe's young bride. Mappin soon finds that this there are plenty of suspects, but Yohe is still at the top of the list. . . . Who Killed the Husband? was published in 1941.

Rene Doria disappears just as he is to marry into wealthy society. Amos Lee Mappin is engaged by the hysterical bride-to-be, and soon stumbles into a murder case with puzzling ties to the past. There are plenty of clues and numerous suspects in this wry look at the upper class and America's infatuation with fame. The Murder That Had Everything was published in 1939.