"All I can do is write the ideas and believe in them and not worry about anything else. I love every aspect of writing. It's totality. That is all there is. Just me and the page and nothing else."
For his latest work he's in the realm of the murder mystery, which he first entered in 2017 with Magpie Murders - a devilishly complicated whodunnit within a whodunnit.
It introduced us to editor Susan Ryeland, her obnoxious, best-selling crime writer Alan Conway and his Poirotesque 1950s private detective Atticus Pund.
Horowitz is now revisiting Susan and Co in Moonflower Murders, another riddle-laden murder within a murder adventure. But there's been a lot of change.