How the number 9 inspired Michael Marshall’s THE INTRUDERS

We’ve just launched a brand new book club over on Goodreads, and in October we’ll be discussing Michael Marshall’s chilling thriller THE INTRUDERS, which will be airing on the BBC this Autumn. We’ll be discussing the book in the group between the 27th and 31st of October, but in the meantime, here’s Michael himself to tell you a little bit about his inspiration for the novel…

The core ideas for my books are cautious in their approach, arriving in dribs and drabs, sometimes over the course of years, until they start sticking together and finally achieve critical mass. There’s a degree of spoiler-dom in this first section if you haven’t read the book, but the trailers for the show have already made it pretty clear what we’re talking about…

THE INTRUDERS was basically inspired by four things:

1. An awareness of how dualized many of us are, in ways major and trivial, how we daily and inherently act and feel as more than one person. How we can be merrily going through our lives, watching our weight, knowing we’re definitely not going to have that cookie, then suddenly finding it’s in our hands and we’ve eaten half of it already. How we can be fascinated by other countries or historical periods, without any obvious reason from our (known) past, deeply consumed by passions that seem to have a life of their own. The secrets people keep, too, the things they’ve done or wish to do, or have happened to them, and how these hidden elements of their psyche define their lives forever. As Carl Jung said, “In each of us there is another whom we do not know.” And he should know, because he’s dead.

2. I was also intrigued at the time by people who seemed to enter the world with an inside track, as if starting the game of life armed with prior experience and a strong following wind. There are many examples, from Mozart’s precocious composition skills, Bach’s apparently effortless genius and other artistic prodigies — to entrepreneurs who were already selling their parents’ possessions back to them at the age of two. My most compelling personal marker is a little-known fellow called Sam Mendes, whom I knew at university. While the rest of us spent the first term flallopping around the place like baffled puppies, newly-released into neo-adulthood and agog with self-doubt and exhilarated confusion, Sam was busy putting together his first theatrical production. I didn’t even know where the theatres were. In time, I was directed in a play by him and we were both part of a barge tour of pubs, performing wordy skits to audiences of perplexed drunkards who’d probably been hoping for strippers. Been decades now since we spoke, but luckily my father keeps me updated on just how jolly well my old acquaintance is faring, which barely causes a beat of chagrin. Sam is an infuriatingly decent guy on top of it all, and when I heard he’d won an Oscar for his first movie my reaction (while howlingly envious, I’m only human) wasn’t one of surprise. Well, yeah, I thought — he would: that makes perfect sense. And good for him.

Though I didn’t care for SKYFALL at all, dude. So there. Ha. Loser.

3. Another trigger was an incident with my infant son and a toy saxophone. Tiny children will go for any old thing with their grabby little hands, raise it to their mouths — and suck on it. But one afternoon I saw Nate pick encountering a yellow plastic sax for the first time, put it to his mouth, and blow. He then picked up something else, and sucked as usual. I’m sure there’s a perfectly reasonable explanation for this, but it made my bleary sleep-deprived mind wonder how he’d known that’s what you did with this particular kind of object…

4. And finally, the number 9 has long fascinated me, almost as if I knew it would one day come to have special relevance. Years back, mainly as an excuse not to write the current novel, I got interested in curiosities of math. To avoid writing a previous book I taught myself to write in hieroglyphs — a skill I have now forgotten, along with all the math stuff (which fell quickly out of a head not fundamentally suited to holding it). I was interested to discover, however, that the number 9 has some fun properties.

Try this, for example: pick a three digit number in which the digits are all different, then reverse it — you could start with 367, for example, and get 763. Subtract the smaller of the numbers from the larger: in fact, don’t do this yourself, but get someone else to do the math, without telling you either number. Then ask them for the last digit of the result, and you’ll be able to tell them the whole number in a way that appears divertingly remarkable. How? The middle digit will always be nine, and the first and last will add up to nine: 763 – 367 = 396. You can then do the process again, with a variation, getting them to pick a new starting number, and allowing them to make their own choice about whether to tell you the first or last digit this time. Feel free to use this nifty trick to score large sums of money in bars. If you do it more than twice and get beaten up, however, you’re on your own.

My son, to whom the novel is dedicated, will be nine years old when the show airs.

Want to talk about THE INTRUDERS? Head over to Goodreads and join the book group!

This post originally appeared on Michael Marshall’s website

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