My games are fitness smartphone adventures – Zombies, Run! and The Walk. In the games you go for a run or a walk in the real world, and we tell exciting adventure stories in your headphones to encourage you to go a bit further, a bit faster, or just to make the whole business of getting some exercise a bit less boring. (Fans of my novels The Power and The Future might detect a certain title style with the latter.) Co-created with the British games company Six to Start, they are real UK success stories. They’ve been downloaded more than 10 million times, helping many people to exercise more. We’re niche for gaming, but within our niche, we’re the most successful smartphone fitness game ever made.