The ongoing popularity of Agatha Christie is a bit staggering. In 2017, Amazon and the BBC cut a multiyear deal to adapt lavish versions of Christie mysteries for television — books that have been adapted many, many times before. Kenneth Branagh’s Murder on the Orient Express, featuring Branagh himself as the famed Belgian detective Hercule Poirot, was a big hit in 2017, despite being an absolutely terrible film. Branagh’s 2020 follow-up, Death on the Nile, was delayed by covid-19 but will no doubt do extremely well on television. With the first Christie adaptation dating all the way back to 1928, what explains this astonishing century-long power?

Generally, it is attributed to Christie’s intricate and unrivaled plotting. A classic example is Murder on the Orient Express (1934). Of twelve likely murder suspects trapped on a snowbound luxury train with a gruesome dead body, whodunit? As Poirot discovers, they all dunit! All twelve apparent strangers have been secretly bound together in a complex international murder conspiracy. Like all of Christie’s best narrative twists, this seemed an obvious invention as soon as she came up with it, yet somehow no one had employed it before her. Similarly, the book that vaulted her to the top of the mystery writing heap, The Murder of Roger Ackroyd (1926), became a sensation because of Christie’s experimental use of an unreliable narrator — a Watson-like doctor, seemingly trying to help Poirot solve the crime, turns out to be the murderer.

But there’s more to Christie’s popularity than her cleverness. It owes just as much to the enduring lure of her “world” — the conservative Victorian milieu of Christie’s childhood, which she recalled as “wonderfully happy.” Her nostalgia for that era forms the bedrock of her sensibility. The daughter of wealthy parents, Christie was raised in a large villa in the resort town of Torquay, among the kind of genteel leisure only a house full of servants can provide.