“Matilda Briggs was not the name of a young woman, Watson,” said Holmes in a reminiscent voice. “It was a ship which is associated with the giant rat of Sumatra, a story for which the world is not yet prepared.”

Conan Doyle was the master of the teaser. The Holmes tales are packed with little throwaway references to past cases, hinting at a world of untold stories, and spawning a healthy publishing industry of pastiche writers who are only too happy to speculate about ‘Merridew of abominable memory’, ‘the repulsive story of the red leech’ or the madness of Isadora Persano, involving ‘a remarkable worm unknown to science’. (Although the one about ‘the politician, the lighthouse, and the trained cormorant’ is taking the mickey, if you ask me.)

These little references give us a hinterland. A confirmation that the character exists outside the page, a sketch of landscape to populate with our own imaginations. If there were no untold stories, some of the magic would be lost.

And then there’s Harry Potter. A massively realised, detailed world, where the author knows everything down to preferred brands of cereal and the parentage of characters who appear once on p.312 – and where the reader hears about it. If JK Rowling had come up with the giant rat of Sumatra, we’d know what part of Sumatra it came from, how giant it was, and that the captain of the Matilda Briggs was a Hufflepuff who once dated Ron Weasley’s aunt.

Remember the fuss when Rowling announced that a ‘major character’ in HP4 was going to die? It turned out to be – I had to look this up – Cedric Diggory, and a lot of people felt very cheated, because he was not a major character by any definition. But in Rowling’s head, he was a major character, because in this massively realised world in her head, everyone was major. There was no Basil Exposition or Jimmy Plotfunction, just there to do a job in the service of the story. Everyone had a fully developed existence. Which, when that information is in the author’s head, informs the text on the page, creating a huge richness and reality.

I tend to think some of it ought to stay in the author’s head.

Many will disagree. A large part of the pleasure in Lord of the Rings / Harry Potter / The Kingkiller Chronicles is the fact that the author puts every possible bit of worldbuilding on the page, and the reader can wallow for hours and know all there is to know.

Me, I don’t want to know all there is to know. I want the author to know it, sure, but I like the sense of a story existing in a larger world. I love China Miéville’s books because of the joyful wastage of invention: he’ll casually toss out a two-sentence mention of some brilliant abomination that anyone else would use as the basis for a trilogy, and then never use it again. (But now we know it’s out there…)

This isn’t an ‘I’m right/you’re wrong’. HP/LoTR etc are vastly popular with good reason. The immersive experience of reading a mammothly detailed series is an incredible one. But the untold story has pleasures too.

I’m thinking about this because there’s a point in The Magpie Lord,  where our hero, Crane, is asked why he has seven magpie tattoos.

“Whim. I was being forced to have a very large and expensive tattoo, and it seemed a change from the usual dragons and carp. I rather liked it, as it turned out, so I added more.”

“…forced to have a tattoo?”

“It’s a long story.”

It’s a long story I didn’t tell the reader (Crane tells it off-page), and quite a few people have commented on this in reviews, wanting to know what happened. I’m delighted to the point of embarrassing public dancing that anyone cares enough to mention it. And yet…

For me, the throwaway line conveys that Crane’s life has been so extraordinary that he regards being forced to have a huge tattoo as, meh, just one of those things. By leaving it as an untold story, the reader can fill in the gap with her own speculations and ideas. As a told story it’s a little piece of his past nailed down, a little mystery revealed. And I wonder if a single truth (about the tattoos, the giant rat, or even that stupid trained cormorant) can be as pleasurable as the imaginative vistas opened up for the reader by not knowing. After all, seven is for a secret never to be told…

Then again, it’s a pretty good story.

Should authors tell all? What do you think?