Six dozen novels, more than 2 billion books sold: for a genteel woman who professed to have no interest in commerce, Agatha Christie did well for herself. She is reckoned to be the best-selling novelist of all time, and even though she has been gone for 40 years and the pace has slackened somewhat, many of her books remain in print and continue to find readers today.

Born in southwestern England in 1890 to a British mother and an American father, Agatha Miller was home-schooled and solitary. She developed a close attachment to both animals and books, bonds that would remain with her all her life, and was particularly fond of the adventures of the Railway Children and the young heroes of Robert Louis Stevenson’s then-new novels. On her father’s death when she was just 11, Agatha went off to school, reluctantly and unsuccessfully, then escorted her ailing mother to convalescence in Egypt, a land that would hold her fascination forever after.

She also began to write, mostly short stories, with a first novel set in Cairo. While on homefront service in the medical corps during World War I, she began to produce work on a rigorous, thought-through schedule, translating her love for Arthur Conan Doyle’s Sherlock Holmes stories into a novel, The Mysterious Affair at Styles, that she wrote after-hours and that found publication first in the United States, in 1920. Its hero was a Belgian refugee in England, Hercule Poirot, who turns his considerable intellect to the problem of determining just which rich Briton has done in another rich Briton—for Christie somehow instinctively knew that readers enjoyed seeing the 1 percent murdered, whether by strychnine or blunt force.

Christie’s most famous production did not star Poirot, who would go on to figure in many other of her books, nor Miss Marple, the rather unlikely detective mastermind of another series of her novels. It began life in 1939 under a title too unpleasant for modern ears, then was reborn under another one only marginally better. Under those titles and as And Then There Were None, it has sold a staggering 100 million copies and emerged as a classic of the British crime genre worthy of ranking alongside the best of Wilkie Collins and Conan Doyle. Somewhat grittier than most of her other books, Christie’s novel has held up better than some of her more static drawing-room whodunits—and indeed, it was announced not long ago that a new film version of the story was in the works, while, in a separate development, Kenneth Branagh would star and direct in a film version of the Poirot vehicle Murder on the Orient Express.

Dame Agatha Christie, whose brief disappearance in 1926 yielded a real-life mystery all its own that hasn’t yet been fully solved, wrote books of a more elegant and less brutal bent than the crime fiction we’ve since taken to reading. It’s hard to imagine what she and, say, Stieg Larsson or Patricia Cornwell might have to say if on a panel together. I suspect they’d agree, though, that it’s fun to dispatch a twitty heir—and so it ever will be.

Gregory McNamee is a contributing editor.