Who is the best-selling fiction writer of all time?
Many, if asked this question, might guess J. K. Rowling, Stephen King, George R. R. Martin, or some other popular writer of the past few decades. It might come as a surprise to most, then, to learn that the author whose works have sold more copies than any other is mystery writer Agatha Christie. Between the publication of her first novel in 1920, and her last in 1975, Christie had sales of over 2 billion books in a career that spanned over five decades. The most popular of her novels, And Then There Were None, sold over a hundred million copies alone, making it one of the best-selling English language novels of all time. She is also the most widely translated author of all time.
Today, audiences continue to thirst for her stories, and the most recent major movie based upon one of her literary works, Death on the Nile (released in 2022), starred such notable Hollywood actors as Gal Gadot, Armie Hammer, Russell Brand, and Kenneth Branagh.
So who was Agatha Christie? What inspired her to write dark tales of passion, greed, and murder, and why was she so massively popular with readers in her own day, and in ours?
A Literary Life
Though Agatha Christie’s novels often feature feuding families who squabble over money, power, and pride, Christie was born in 1890 to a quite ordinary upper-middle-class family in the English seaside town of Torquay. She had a happy, peaceful childhood, and was tutored at home by her family in reading, writing, arithmetic, and music. Like many other authors, she was a precocious  child, and read voraciously from an early age, with a particular fondness for Victorian novelists such as Sir Arthur Conan Doyle, famous for his Sherlock Holmes books.
Christie’s father’s death when she was 11 years old introduced financial hardship to her family. She was sent for many years to study music at a boarding school in Paris, but ultimately gave up on her goals of being a concert pianist or opera singer. In 1912, at the age of 24, she married Archibald Christie, who was a military officer in the Royal Artillery.
Within two years, he was called to serve in the First World War. Agatha decided that she couldn’t simply wait out  the War at home, and instead volunteered as a nurse with the Red Cross. Later, she would use the knowledge she gained of poisons and antidotes in her detective novels. While other mystery novelists had relied on imaginary poisons, with medically impossible effects, Christie insisted upon medical accuracy.
After the War, the Christie family returned to Torquay where they had their first and only child, and lived among many refugees who had fled the War on the European continent. She would ultimately base her most famous character, the fussy Belgian detective Hercule Poirot, on the many soldiers and refugees from Belgium who she treated as a nurse.
Her husband gained a low-paying job in business, and Christie began to submit her stories for publication, which were immediately popular. Soon, she was the breadwinner  in the family, but marital difficulties followed. After her husband asked for divorce, admitting that he had fallen in love with another woman, Christie disappeared. Her car was found parked at the side of a road, but there was no sign of her.
The shocking disappearance of the popular author became a major news story. Ultimately she was found after 11 days, checked into a hotel under a false name, claiming to have suffered amnesia. Some biographers of Christie believe she had a mental breakdown due to stress; others believe that she had intended to embarrass her unfaithful husband, who she then divorced.
Christie’s later life was much calmer. She remarried, to an archaeologist, and their global travels provided the material for some of her most famous works, including Murder on the Orient Express and Death on the Nile. Her books continued to break sales records, and in 1950 she was elected a fellow of the Royal Society of Literature. Ultimately, she was honored by Queen Elizabeth II as a Dame Commander of the Order of the British Empire.
A Formula for Success
Christie’s novels are generally recognized as exemplifying the “Golden Age” of detective fiction. One characteristic of this style is that brutal crime occurs in unexpected locations that we might otherwise think of as safe, comfortable, or even cozy.
Many of her 66 detective novels follow a familiar formula: set in a quaint village in the English countryside, an old aristocratic family fights over money and inheritance, with a supporting cast that involves their domestic help—the butler, the cook, the maid—as well as local figures from the community—the doctor, the lawyer, the policeman. In the end, the detective gathers the characters together and solves the case before their eyes, with plenty 0f red herrings  thrown in to distract the reader.
Despite her reliance on this formula, the popularity of Christie’s works ultimately stems from their ability to surprise the reader. Christie’s readers challenge themselves to “solve” the murder before the ending of the book, but Christie throws in lots of twists  and turns that make this very difficult, and often, the murderer is the character you would least suspect—sometimes even including the the book’s narrator. Many of the “twists” which Christie originated have been adopted by later authors, and her influence on the mystery and detective genres remains strong.
The “Queen of Crime” today
Christie herself, always a bit old-fashioned, was not a big fan of movies, much preferring books and theater. It is a bit ironic, then, that her books have been so regularly adapted for cinema, television, and even video games. In fact, her books have been adapted into movies over 30 times, first in 1928, and most recently in 2022.
The 1974 adaptation of Murder on the Orient Express includes legendary actors and actresses including Lauren Bacall, Sean Connery, Vanessa Redgrave, and Ingrid Bergman, who won the Academy Award for Best Supporting Actress. Much more recently, the book was adapted again in 2017 with an equally impressive cast, including Michelle Pfeiffer, Johnny Depp, Daisy Ridley, Penélope Cruz, and Willem Dafoe.
Following Death on the Nile, Director and actor Kenneth Branagh has stated that he intends to make further sequels that would include other major characters from Christie’s works, such as the grandmotherly Miss Marple, with the goal of creating a “cinematic universe” of Christie’s works. Given the ongoing popularity of her works, on page and on screen, it seems that audiences have continued to enjoy trying (and failing) to “solve” Christie’s ingenious mysteries.