Here’s how it happened: I’d just submitted Splinter in the Blood to my agent (Felicity Blunt), expecting it to go out with more of a whimper than a bang—and it confounded my wildest expectations, receiving keen interest from publishers worldwide. This was 2017, the genre du jour was domestic noir, and Splinter was a serial killer thriller—my first, after publishing 12 crime and mystery novels, and the fulfillment of a twenty-year ambition. A self-indulgent treat that might be seen as self-destructive, given that it seemed the publishing world was focused elsewhere, but at that point, I wasn’t thinking beyond Splinter: you see, I’d convinced myself that novel #13 would be my last, so I thought, What the heck… The London Book Fair was just days away, interest was hotting up, and multiple bids were on the horizon. But one of the foreign rights scouts wanted to know about the next book. Did I have any ideas, Felicity wondered, “Even a para you could put together?” As a rule, I start jotting down notes and ideas about the next book two-thirds the way through the one I’m currently writing. This time, I had nothing—why would I, when book thirteen was sure…