[MYSTERY WRITERS]. CHRISTIE, AGATHA (1891-1976). Photograph signed ("Agatha Christie"), n.p., n.d. [circa 1940]. 215 x 164 mm. (8½ x 6½ in.) including margins. A bust portrait of the "Doyenne of the English detective novel," signed on the upper portion of the image -- SIMENON, GEORGES (1903-1989). Postcard photograph inscribed and signed ("Georges Simenon"), n.p., n.d. [circa 1969]. 145 x 103 mm. (5¾ x 4 1/16 in.). A shoulder-length portrait of the Belgian-born detective writer, inscribed and signed on the lower portion of the image: "To my American young friends Sincerely Georges Simenon 1969") -- MARSH, NGAIO (1899-1982). Photograph signed ("Ngaio Marsh"), by Mannering and Associates Ltd. (imprint on verso), n.p., n.d. [circa 1970]. 162 x 114 mm. (6 3/8 x 4½ in.). A standing portrait of the writer, with hands folded, signed on her sleeve. (3)