One hundred and twenty five years ago, a baby girl was born to an American father and an English mother in the Victorian spa town of Torquay. The youngest child of three who adored mathematics and learned to read on her own, her upbringing was solidly upper middle class with all the privileges it entailed – the coming out season, the finishing school, the cruise and holiday in the Near East, the assurance of her milieu and the times she grew up in – for the British Empire was at its peak at the time.

There were no indicators of exceptional ability but for her obsessive need for privacy, her solitary play that would retreat effortlessly into imagination and in her youth, a stubborn streak combined with an impulsiveness that would lead her to marry an officer at the RFC at the beginning of the Great War after a whirlwind romance.

The same stubborn streak and impulsiveness also led her to write her first book as a result of a bet with her elder sister. Her choice of a Belgian detective when she knew nothing about the country or its people was as impulsive as her marriage. Yet, miraculously, she became an overnight publishing sensation, gaining worldwide popularity.

People loved her plot puzzles and she did not disappoint. Her extraordinary inventiveness leaped across protocol as she invented the detective story written from the murderer’s POV, the joint murder of one person by a group, the murder committed by (seemingly) no one, the one that a child commits, apart from all the other plot structures that were conventional. She touched the genre of detective stories and turned it on its head. In 1976, when she died, she was outsold only by the Bible.

The world has changed irrevocably since Agatha Christie stopped writing, perhaps into one she dreaded, as some of her later works betray, yet she is read more than ever before; her stories are repeatedly adapted for the stage, the big and the small screen, across countries and languages.

What makes Christie endure so? Apart from the reasons of plot and inventiveness, which have been written about extensively, I wanted to look into her writing itself for clues. It is tempting to present a little treatise on what I found, but why spoil the fun when Agatha herself can give you the answers?

So here are my reasons why, presented in her own voice from her books:

Refreshingly contemporary

Consider the lines below, which could have been uttered by any young girl of today:

“ 'Father’s a dear – I’m awfully fond of him – but you’ve no idea how I worry him! He has that delightful Victorian idea that short skirts and smoking are immoral. You can imagine what a thorn in the flesh I am to him!’ "
~ Tuppence in The Secret Adversary

Funny then and funny now

One gets a glimpse of a mischievous mind behind many of her passages. They are not laugh out loud funny, as befits the detective fiction genre, but they are frequent and each one merits a chuckle.

“Take this Hercules – this hero! Hero, indeed! What was he but a large muscular creature of low intelligence and criminal tendencies!...
The whole classical pattern shocked him. These gods and goddesses – they seemed to have as many aliases as a modern criminal. Indeed, they seemed to be definite criminal types. Drink, debauchery, incest, rape, loot, homicide and chicanery – enough to keep a juge d’instruction constantly busy. No order, no method.”
~ Poirot frets in The Labours of Hercules

An unabashed, passionate romantic

And poetically articulate about it, too.

“ 'It is that, is it not, my friend? It is love that has come – not as you imagined it, all cock-a-hoop with fine feathers, but sadly, with bleeding feet.' ”
Poirot to Hastings in The Murder On The Links

The woman’s perspective

Christie articulated women’s thoughts better than anyone in popular fiction. I am very surprised that this is not written about enough. She understood and fearlessly wrote about women’s innermost desires. The little gem of a piece below is a dialogue between Bundle, the young and vivacious wife of the vicar at Miss Marple’s village, and her repressed but closet romantic husband, who is a good twenty years older than her:

“ ‘The others thought me simply wonderful and of course, it would have been very nice for them to have me. But I’m everything you dislike and most disapprove of, and yet you couldn’t withstand me! My vanity couldn’t hold out against that. It’s so much nicer to be a secret and delightful sin to anybody than to be a feather in their cap. I make you frightfully uncomfortable and stir you up the wrong way the whole time, and yet you adore me madly. You adore me madly, don’t you?’
‘Naturally I am very fond of you, my dear.’”
~ The Murder In The Vicarage

A wise old woman, too

She was a past master at old, womanly wisdom.

“ ‘He’s such an odd young man – says the most disturbing things sometimes. He’s supposed to be clever, you know,’ said Miss Bunner, with frank disapproval.
‘Cleverness isn’t everything,’ said Miss Marple, shaking her head.”
~ Miss Marple and Miss Dora Bunner gossiping over tea in A Murder Is Announced

Knowing me knowing you

She had an instinctive understanding of human nature and prescient about how it could morph. The lines below explain our reluctance to think through issues, or to learn from history. They could belong to today’s India in a heartbeat.

“What a world it was nowadays… Everything used the whole time to arouse emotion. Discipline? Restraint? None of these things counted for anything anymore. Nothing mattered but to feel.
What sort of a world …. could that make?’
~ Passenger To Frankfurt

Nothing endures like a mystery

Which brings me to the one plot Agatha Christie never wrote and barely acknowledged – that of the spurned wife faking her own death to implicate her philandering spouse. On December 3, 1926 at the peak of her fame, Agatha was shattered when her husband Archie Christie, asked her for a divorce so he could marry his secretary.

The next day she disappeared, leaving her car in a bush at the edge of a quarry in Surrey, gears in neutral, brakes off, with her clothes bundled in there. All she took were some sheets of writing paper.

Twelve days later, after the biggest manhunt that Britain had ever seen, when Archie had been taken in by Scotland Yard “to assist with the enquiries”, Agatha was found in the White Swan Hotel at the spa town of Harrogate.

Oddly, she had assumed the name of her rival, Nancy Neele. Her family, including Archie Christie, maintained that she had suffered a bout of amnesia. But then why stage her own death? Agatha herself was stubbornly silent throughout her life, never alluding to the affair. It is therefore, completely absent in her autobiography.

But even as she turns an immortal 125 on September 15, Agatha Christie’s last unsolved mystery remains alive in the public imagination. In 1979, the film Agatha was based on this episode and starred Vanessa Redgrave and Dustin Hoffman. It is also the plot that catapulted Gone Girl to worldwide acclaim in 2012.

Jash Sen is an Agatha Christie obsessive and the author of The Wordkeepers and its sequel, Skyserpents.