If you’re one of the 100,000 people who downloaded James Oswald’s book Natural Causes last month you’ll already understand why he’s been such a hit. He writes supernatural-tinged crime novels that seem perfect for fans of authors like Will Carver. Dark and complex, Oswald’s writing reaches out and grabs you by the throat. This weekend the next instalment hits the market and James has joined us to discuss it…

Tell us a little about The Book of Souls?
On the night of the Millennium, while everyone else was out celebrating, Detective Constable Tony McLean discovered the body of his fiancée, naked, staked out in the Water of Leith. She was the 10th and last victim of Donald Anderson, the notorious Christmas Killer who terrorised the women of Edinburgh for a decade.

At his trial, Anderson claimed he was influenced by an ancient book, The Book of Souls, but the jury saw through his attempt at an insanity plea and he was sent down for life. Anderson is killed by a fellow inmate 12 years later. Then the body of another young woman is found, naked, staked out in running water.

Natural Causes, has had over 100,000 downloads in one month and received 50 five-star reviews on Amazon UK. How have you got there?
I honestly have no idea. There was no marketing plan beyond giving the book away to try and entice people into buying the second one. It hit the top of the charts in a couple of days and has been in the top five ever since. Once you’re at the top of the Amazon free chart, I guess it’s self-perpetuating. You get exposure so more people download the book so you get greater exposure. The reviews have been a very pleasant surprise.

Unlike most self-published authors you’ve avoided marketing yourself via social media, why is this?
I’m just not very good at blowing my own trumpet. Also in the last 18 months I’ve taken over a 350 acre livestock farm, so I don’t have the time to spend properly pushing the book, nor do I really understand social media. Luckily for me, others have decided to take it upon themselves to help me. A mention here, a retweet there – it all adds up.

Word of mouth is the most potent marketing tool. I’ve just sent a free copy of The Book of Souls to all the people who’ve emailed me and told me how much they enjoyed Natural Causes. It’s not a huge number, but hopefully they’ll tell their friends about this great new author they’ve discovered.

There was quite a delay between writing Natural Causes and its publication, what prompted you to go ahead finally?
Frustration, mostly. That and the glacially slow nature of the submissions procedure. Pretty much every rejection letter I’ve ever had has gone along the lines of, ‘We love your writing, but we just don’t know how to sell it.’ Apparently the subtle blend of crime and supernatural doesn’t go down well. Fans of John Connolly might find that faintly insulting, and there are more and more authors ignoring the genre boundaries these days. Sarah Pinborough’s Dog-Faced Gods trilogy is a good example, and Ben Aaronovitch’s London series.

Your earlier work was fantasy, how have you found the transition to crime?
The keen-eyed readers out there will notice that I haven’t entirely given up my fantasy roots. When I wrote Natural Causes, I was very poorly read in the genre – a few Rebus books, some Agatha Christie, a couple of RD Wingfield’s Frost books and all of Stuart MacBride’s Logan McRae novels. I’ve known Stuart for far too long – Detective Inspector McLean first appeared in a comic strip we collaborated on back in the 90s – and he was the one who turned me to the dark side. I’ve written a straight thriller since finishing the two McLean books, but I love the freedom to invent that fantasy gives you.

Perhaps my biggest worry with crime fiction is getting fundamental aspects of procedure wrong. I’m not an obsessive researcher, and dread the prospect of approaching actual police officers for information. But one of the first people to contact me about Natural Causes was a retired Lothian and Borders detective, who congratulated me on my attention to detail, much to my surprise. The other shoe will drop soon enough when someone points out some howler or other that I’ve made, but for the moment I seem to have gotten away with it.

Author Damien Seaman suggested that your success represents a disconnect between publishers’ perceptions of the market and readers demands, do you agree?
I think it’s very difficult for publishers to know what will sell and what won’t. If I was betting the sort of financial investment involved in launching a new author, then I’d probably stick to the more conventional storytellers too. The problem is that if you keep on churning out the same thing, readers will get bored and go elsewhere. There are more books crossing the genre barriers now, so maybe publishers are getting wiser to audience preferences. With the huge resurgence in vampire and zombie stories in all media, it’s hardly surprising if they begin to turn up in crime fiction. I was just ahead of my time, obviously. I self-published my first ebook in 2004, and sold one copy. Trail blazer, that’s me.

What’s coming up next for you?
Well, there’s still two cows to calve, and if the rain ever stops then I’ve got to shear the sheep… Oh, you meant writing? Next in the pile is the third book in my fantasy series, The Ballad of Sir Benfro, then I’m going to dig out a treatment for the third McLean book. It’s called The Hangman’s Song, and that’s all I’m giving away right now.