Last summer, while browsing in a used bookstore in San Luis Obispo, Calif., I discovered something I thought no longer existed ― an Agatha Christie novel I had not read. Anyone monitoring my vital signs would have thought I had discovered the next Gnostic gospel or a lost play of Shakespeare’s. Clutching it tightly as if someone might snatch it from me, I quickly bought it. I promised myself I would take my time, savor the experience and read only a few pages at a time. Instead, I finished it the next day.

Now it resides beside its sisters in my Agatha box, a crate at the foot of my bed. I don’t own all of the 66 mystery novels and 14 short-story collections that Christie wrote, but I have most of them and I read them over and over again, in rotation, throughout the year.

I read lots of other books as well, but I don’t like to go too long between Agatha Christies because, as a writer myself, I don’t like to stray too far from the masters. And for anyone trying to write to be widely read, it’s hard to beat Dame Christie. With deft and cheerful economy, she can conjure a character in three sentences, set an intricate plot moving in five and plumb the depths of the human soul using snatches of overheard conversation and a bottle of hat paint.

She believed in storytelling and did not confuse it with decanting the contents of her interior life and stretching it out along a contrived plot tarted up with simile, symbolism and encyclopedic information about secret societies (although she did love a good secret society now and then, ditto the occasional plot to secure world domination).

Her life story “Agatha Christie: An Autobiography” (Harper, $29.99), which has just been rereleased with a new foreword by her grandson, is similarly brisk and admirable, although at 532 pages, it is quite the longest work she wrote. Capturing the experience of a generation too often made over-grim or over-glorious, it is the autobiography of a woman, not merely a writer. Yes, she admits that even as a child she was telling stories to the kittens in the garden, but her work was her work and just one of the things that made up her life, which survived two world wars, two marriages and an unprecedented career in a way that can be described only as globe-trotting.

During her marriage to archaeologist Max Mallowan, she spent as much time working on various excavations as she did writing novels, which not only inspired several of her novels (including the ancient Egyptian “Death Comes as the End”), it makes her a double-shot inspiration for Elizabeth Peters’ popular archaeologist detective, Amelia Peabody.

Not that there are many mystery writers who don’t owe Christie something. The genre was popular long before she took a stab at it with “The Mysterious Affair at Styles” (which sat in the publisher’s office for five years before it was accepted for a pittance and published in the early 1920s), but it was much more hidebound. Hercule Poirot entered loudly dismissing all the old familiar tropes, declaring that it was not for him, this Holmesian propensity for scrambling around in the dirt collecting cigarette ash and bits of burnt letter; instead the work was done by the little gray cells.

Tommy and Tuppence Beresford were the postwar adventurers, creating a whole new template for romance with their thrill-seeking banter, and the popularity of Miss Marple began the race for Most Unlikely Detective, in this case, a spinster of a certain age who used her hard-won understanding of human nature to solve crimes.

Yet there are those too who dismiss Christie simply because she was so prolific, because her books eschew the epic or deeply psychological in favor of a story best told quickly and with deceptive ease. And yes, the genre has changed, grown darker and more brutal (a shift Christie deplored as early as 1975), but as a die-hard fan I don’t want to hear the word “formulaic” (she invented that formula, people, she can use it as she will), “predictable” (I defy anyone to find me a better, or more surprising, motive for murder than the one in “The Mirror Crack’d” or better crimes than those committed in “Curtain” or “Murder on the Orient Express”), and I don’t want to hear the term “cozy.”

Agatha Christie was not cozy. She earned the title the Queen of Crime the old-fashioned way ― by killing off a lot of people. Although never graphic or gratuitous, she was breathtakingly ruthless. Children, old folks, newlyweds, starlets, ballerinas ― no one is safe in a Christie tale. In “Hallowe’en Party,” she drowns a young girl in a tub set up for bobbing apples and, many chapters later, sends Poirot in at the very last minute to prevent a grisly infanticide. In “The ABC Murders,” she sets up one of the first detective-taunting serial killers.

The signature country home aside, Christie’s literary world was far from homogenous. Her plots, like her life, were international, threading through urban and pastoral, gentry and working class, dipping occasionally into the truly psychotic or even supernatural. Christie murders were committed for all the Big Reasons ― love, money, ambition, fear, revenge ― and they were committed by men, women, children and, in one case, the narrator. Some of her books are truly great ― “Death on the Nile,” “And Then There Were None,” “The Secret Adversary,” “Murder on the Orient Express,” “Curtain” to name a few ― and some are not. But even the worst (“The Blue Train,” “The Big Four”) bear the marks of a master craftsman. Perhaps not on her best day, but the failures make us appreciate the successes, and the woman behind them, that much more.

To a modern eye, her books reflect many of the faults of her generation ― “And Then There Were None” was originally titled “Ten Little Niggers” (which was also the original title of the poem changed to the only slightly better “Ten Little Indians”), and the British class system, still in place when Christie grew up, is often replicated in her books without question or argument.

That said, there were no sacred cows ― her murders were as socially diverse as her victims, and Poirot’s greatest asset was that, as a foreigner, no one thought him important enough to guard against. Through him and his less-than-perceptive British foil, Hastings, Christie was able to dissect the famous British reserve and rigid dictates of class. The running joke that no one seemed capable of believing that, although he spoke French, Poirot was in fact Belgian, served as a perpetual admonishment against Britain’s often dismissive relationship with its European neighbors.

But it was Miss Marple who became the most vivid symbol of Christie’s worldview. With her white hair, cornflower blue eyes and gentle ways, Miss Marple took a lively interest in the world around her but knew from experience, alas, that pretty much everyone was capable of anything, including murder. People can be wonderful creatures, my dear, she would inevitably say, but still it pays to keep your wits about you.

It’s a dictum that has lost neither its social nor literary resonance, though it’s difficult to think of anyone since who has wielded it more effectively. The problem was never that Christie wrote too many books but that she wrote too few.

By Mary McNamara

(Los Angeles Times)

(MCT Information Services)