by Charles Finch

Agatha Christie has remained a towering figure in the mystery genre, even as her specific style has moved into various genteel retirement communities – the cozy, the historical, the pastiche. "Magpie Murders," the British author Anthony Horowitz's sleek, fun, cunning new novel, is a complex reckoning with Christie's immense popularity, and what it says about us as readers.

An editor named Susan Ryeland narrates the first few pages of the novel, just long enough to introduce – well, Magpie Murders, a manuscript by her best-selling author, Alan Conway, which, she says cryptically, has changed her life, costing her a job, a house and more.

Horowitz then launches into this novel-within-a-novel, a flawless imitation of the Golden Age mysteries of Christie, Ngaio Marsh, Margery Allingham. His detective is Atticus Pünd, who speaks with the "perfect, studied English of the cultivated foreigner, enunciating every syllable as if to apologise for his German accent," the kind of magical outsider (a dandy Belgian, a meddling old woman) that Christie loved to drop into settings of starchy English self-regard.

The year is 1955 — late in the era, but it's Conway's ninth Pünd mystery — and takes place in a picturesque village called Saxby-on-Avon. A woman named Mary Blakiston dies, and after everyone has very solemnly mourned her they take turns telling Pünd what a gossip and scold she was. This leads him to a number of plausible suspects, from the piggish local squire to a shifty antiques dealer to a roustabout gardener. Horowitz captures Christie's uncanny ability to glide at lark's height over a village's inhabitants, exposing their little weaknesses, dreams, secrets; everyone, even if it's not murder, is guilty of something.

Then this perfect novel ends, abruptly and without a solution.

"Annoying, isn't it?" Susan Ryeland comments upon her return, in the chatty first-person voice of the book's back half. More than annoying, in fact; soon she'll learn that Pünd's creator has been found dead. She immediately realizes that his death has elements of mystery in itself, however. Did he jump, or was he pushed? Was he about to change the will that left his fortune to his young lover? And where have those final few chapters gone?

Cautiously, Susan begins to play detective, and Conway, mirroring Mary Blakiston, emerges as a loathsome figure. As Susan searches for the missing chapters that will complete the novel (and give Pünd his delayed solution, a tantalizing and clever touch), she discovers that Conway was mean-spirited and petty, filling his books with cruel acrostics, anagrams, internal jokes and caricatures. (Pünd – punned, get it?) Any one of a number of people might easily have wanted him dead.

Each of the narratives in "Magpie Murders" is engaging and fluid, each with its own charm, though Horowitz's joyful act of Christie ventriloquism is, in particular, spectacularly impressive. He's a silky, gifted author, as he's demonstrated previously in his two very fine homages to Sherlock Holmes, as well as a pair of television shows, "Foyle's War" and "Midsomer Murders."

And a probing one. In this nested tale, Horowitz seems to be querying his genre's essential paradox: how often it's a refuge, comfort reading. "Death," as Dorothy Sayers once observed, "seems to provide the minds of the Anglo-Saxon race with a greater fund of innocent amusement than any other subject." The plotting and the solution of Pünd's half of "Magpie Murders" are far tidier and more satisfying than Susan's faltering, bloody, ugly investigation. Which do we want, Horowitz wonders, a safe murder or a dangerous one? Only since Agatha Christie has it passed into the stewardship of readers to make precisely that decision.

Charles Finch is the author, most recently, of "The Inheritance."

magpie murders

By Anthony Horowitz

Harper. 236 pp. $27.99