Zombie books were going to be my passion projects, but certainly not pay the bills. I thought I was going to have to get a real job on a sitcom or something, and have my zombie books to remind myself I was still a writer at heart. I never thought I could actually pay my bills and write what I wanted.

When I started writing, there was nothing about zombies. It was all teen movies, which to me are scarier than zombies, but that's another story.

The dead walk among us. Zombies, ghouls-no matter what their label-these somnambulists are the greatest threat to humanity, other than humanity itself.

Zombies will try to scale any surface no matter how unfeasable or even impossible. In all but the easiest situations, these attempts have met with failure. Even in the case of ladders, when simple hand-over-hand coordination is required, only one in four zombies will succeed.

I wrote 'The Zombie Survival Guide' because I wanted to read it, and nobody else was writing it. All I've been doing with everything I've written is answering questions that I had.

We live in such a service-based, globalised economy where very few people actually make anything and the people who do make stuff... it's all part of a massive global supply chain. So what if all those chains were suddenly cut, how would you make something? How would you keep people alive? And that was something I wanted to explore.

I actually wrote my first zombie book way before I got the job on 'Saturday Night Live.