‘Duchess of Death’ by Richard Hack

Agatha Christie, history’s bestselling novelist, always had a special relationship with Christmas. When she was a child, it was the occasion of happy memories before and after the turn of the 20th century. Once she became a prolific and popular author, the holiday was a marketing hook for her English publisher, who for decades urged customers to give “a Christie for Christmas.”

And it was at Christmastime in 1926 that Christie lived through the most dramatic episode of her life: an 11-day disappearance that made headlines throughout Britain, had thousands of citizens seeking her whereabouts and -- after the wayward writer was found in a resort hotel in northern England, registered under the same last name as her then-husband’s new love interest -- was brushed aside as “memory loss” and never publicly explained.

Richard Hack makes the most of Christie’s sensational disappearance in “Duchess of Death,” an “unauthorized biography” said to draw “from over 5,000 unpublished letters, notes, and documents.” He devotes some 50 pages to a vivid re-creation of the author’s movements and, by his creative reckoning, her motives in fleeing: Prompted by husband Archibald’s demand for a divorce, she carried out a planned itinerary as elaborate as any of her timetable-pegged murder mysteries. It was a romantic scheme meant to provoke her disaffected spouse to “rescue” her and return them both to the sanctuary of a once happy marriage.

Fair-play plotter that she was, Christie (whose most recent book at the time of her vanishing was the notoriously innovative “The Murder of Roger Ackroyd”) left clues to her destination in notes to her husband and her secretary, and in a letter mailed after she’d left. But circumstances conspired to prevent those hints from being heeded.

The chief impediment was the obtuse behavior of a supervising police inspector whose wrong-headed deductions would have tried the patience of even Christie’s diplomatic fictional sleuth, Hercule Poirot. This real-life detective, his actions documented daily in newspapers Christie was reading, persisted in combing the countryside around the author’s home in Surrey rather than the Yorkshire district at which she’d taken pains to point.

“Yorkshire, you idiot!” a hotel maid heard the still-in-hiding novelist shout one day in frustration.

By the time Christie was found, even she could see her marriage was over. But before long, she found a more companionable mate for the rest of her life: archaeologist Max Mallowan, with whom she willingly spent much of each year at digs in the Middle East or traveling in other lands.

Wherever she went, Christie continued to produce prose at a formidable rate: 95 books in all, translated into 105 languages. With cumulative worldwide sales of 2 billion copies, she was the McDonald’s of the mystery genre -- or, as she was wont to call herself, its “sausage machine.”

She also wrote for the theater: Her plays included “Witness for the Prosecution,” a hit in London’s West End and on Broadway, and “The Mousetrap,” which opened in 1952 and became the longest-running show of all time. (It’s still running.) Film and television adaptations have extended Christie’s influence to the present day.

Happily, the “duchess of death” behind all this creative mayhem was the most unprepossessing of authors. One doesn’t envy the biographer of this self-deprecating woman who ignored reviews, made no claims for literary excellence or even writerly skill and whose greatest vice was the ingestion of a high-caloric, high-cholesterol beverage that mixed clotted cream with milk. Hack proves up to the mark, however, crafting a work that succeeds (as did its subject) in keeping us turning pages to the end.

Christie’s career did yield a few instances of mild conflict: an onerous tax situation that led to her giving copyrights of many later works to relatives and a wrangle with Metro-Goldwyn-Mayer over a series of films that travestied her Miss Marple character.

But for the most part her life was blissfully, almost perversely, bereft of incident and intrigue.

Except for those 11 days in 1926.

Nolan is the editor of Ross Macdonald’s “The Archer Files: The Complete Short Stories of Lew Archer, Private Investigator.”