It boasts many lyrical sentences, particularly in the final chapter, but "The Christie Affair" feels like it was abandoned in the middle of the editing process. Nina de Gramont's narrator is secretary Nan O'Dea, who is having an affair with her boss, the husband of mystery writer Agatha Christie. It's 1926, the year Christie actually did disappear for more than a week after husband Archie left her for his secretary, Nancy Neele (de Gramont uses real names but changed Neele's).

Christie never explained her disappearance, which has inspired many speculative accounts, including the film "Agatha." Eventually, we discover that de Gramont has concocted an intriguing if implausible theory, but it's a struggle getting there because Christie, the lone sympathetic person in the story, is only a minor character and because O'Dea is such a confusing narrator.

De Gramont spends far too much time on O'Dea's repetitive back story, invents a murder mystery but gives us no clues to solve it, muddles the timeline and, worst of all, has O'Dea describing events for which she could not have been present and diving into the thought processes of people she doesn't even know.

The Christie Affair

By: Nina de Gramont.

Publisher: St. Martin's Press, 320 pages, $27.99.