A tantalizing triptych by the master mystress reissued here: They Came to Baghdad introduces charming Victoria Jones who unwittingly prevaricates her way into a nest of would-be monarchs planning to rise like phoenixes on the ashes of a dead world; N or M? features a husband and wife team trying to ferret out a Nazi "Fifth Column" of British traitors during World War II. . . and finally Murder in Mesopotamia finds Hercules Poirot continuing an auspicious career by solving the murder of a woman who had been receiving threatened letters from a dead (?) husband. The latter is a work of involuted art and all three are a cliff-hanger-on's delight.