This second of two volumes, the first an Edgar nominee, explores the seemingly chaotic, undated, and sometimes barely legible notebooks in which Christie interspersed ideas, plot outlines, and casts of characters for her novels, plays, and stories with shopping lists, reading lists, and other ephemera. Curran, an Irish literary adviser to the Christie estate, organizes it all with admirable thoroughness, often bringing together material on a given title scattered among several notebooks. The first volume’s arrangement was mainly topical, bringing together titles with a theme or type of background in common; the second is chronological by decade from the 1920s to the 1970s. Though the inclusion of two previously unpublished Poirot stories in the first volume and an alternate version of a Miss Marple in the second serve to attract a wide audience of fans, the real appeal of the books is to specialists and scholars. Solutions are routinely revealed, with warnings in the chapter headings. Curran’s critical differentiations add to the interest. Special features of the newer volume relate Christie’s work to the detective-story rules of Van Dine and Knox, list her favorite novels and short stories with Curran’s comments, and offer an early denouement of The Mysterious Affair at Styles in which Poirot elucidates his solution from the witness stand.