It is easy to look at a shelf of Agatha Christie novels and imagine that the world always knew what she could do. The beginning was rather less certain. Her first detective novel grew from a challenge by her older sister, Madge—and then had to survive six publishers saying no.

A challenge between sisters

Christie had already tried poems, stories and a novel before attempting a full-length murder mystery. Madge's challenge gave that next experiment a particular shape: could Agatha write a good detective story? During the First World War, while working in a hospital dispensary, she began to work out an answer.

Her surroundings offered practical material. She was learning about medicines and poisons. For a mystery writer considering a murder method, that knowledge had obvious possibilities. Quiet intervals at work gave her time to think about a plot, its victim and the people who might want that victim dead.

Finding a detective of her own

Christie knew the Sherlock Holmes tradition, but needed her own investigator. Belgian refugees who had settled in Torquay helped suggest a possibility: a former Belgian policeman, displaced by the war, with a formidable mind. Hercule Poirot began to take shape.

The writing was not effortless. According to the account on Christie's official website, she drafted chapters by hand and typed them on her sister's old typewriter. She also cut back an overabundance of clues and twists. Even this most famous constructor of puzzles had to learn what to leave out.

The manuscript that kept coming back

Finishing the book did not mean finding a publisher. The Mysterious Affair at Styles was rejected by six publishers; about four years passed before it appeared. The Bodley Head eventually accepted it, with revisions still to come.

For me, that is the encouraging part of the story. We know Poirot's place on the bookshelf now. Christie, sending out that first manuscript, could not. A finished draft and a returned envelope were immediate facts; a long career was still an unknown.

What began between two sisters became a detective readers would follow for generations. But first, someone had to accept the challenge—and then keep going when finishing the work did not bring an immediate yes.