Paul Murray: 'I've always liked the idea of parallel worlds'

CD: I was much impressed with your accurate depiction of life in a classroom. Have you ever been a teacher?

PM: Apart from a brief and unhappy stint teaching English to a Catalan businessman, who pointed out many faults in my grammar I had not known about hitherto, I've never taught. But I have close friends who are teachers, in very different schools, and I've always found their stories fascinating. It's such an incredibly important job and I really admire anyone who can do it well. For Skippy Dies, I drew on my friends' experience in the classroom, but I also remembered my own schooldays quite vividly. I have a pretty poor memory, but when you spend 10 years in the same place it tends to etch itself in.

CD: There are lots of great characters in Skippy Dies, all of them very well drawn. Did you have a favourite character?

PM: The supporting characters in the book, because less rested on them, were a lot more fun to write. There's a character called Mario who's kind of a sex maniac, I like him a lot. But I think my favourite is a boy called Geoff Sproke, who's just this tremendously nice kid and has somehow escaped the cynicism that's infected everyone else. He's got a love of bad jokes and a fear of jelly.

CD: You got string theory (or the M-theory variant) into the book and I thought it worked very well. Why string theory? How did you come across it?

PM: I came across it on a BBC documentary I turned on quite by accident one Valentine's day. I was immediately fascinated. It's incredibly complicated, so complicated that they can't even agree what the M stands for. And at the same time it comprises this very graceful, very beautiful idea that all matter and energy are simply vibrations on superstrings, so the universe is a kind of music…

When I was younger I read a lot of sci-fi, and I've always liked the idea of parallel worlds – of which there's a long, long tradition in Irish literature and folklore. That aspect of M-theory — that our universe may be one of an infinite number, floating in 11 dimensions — really appealed to me. Also, the idea that reality is just not explainable. The claim that we can master reality — or even one facet of it, economics or demographics or whatever — I find really offensive. Even when it ends in disaster, and all the experts are proved comprehensively wrong, as happened with the credit crunch, people will still line up to listen to whatever huckster appears next. I like M-theory because it seems to conclude that reality is fundamentally beyond our understanding.

CD: Did you have to do any special research to write the book?

PM: Well, M-theory and string theory are really quite difficult and I had to read quite a lot before I felt comfortable writing about them. There's also some material about World War One. At first, I didn't know what aspect of the war I wanted to write about. I went into the library and was confronted with literally thousands of books. Eventually I realised that for me to have any chance of saying anything original about the war, I needed to approach it from an Irish perspective, so I started reading up on the experience of Irish soldiers during the war. I'd known nothing about it beforehand, though I did history in school. Something like 50,000 Irishmen went to fight in the trenches alongside the British, and it's simply not in the schoolbooks. I found all kinds of fascinating material. In 1916, while the Easter Rising was being put down quite brutally by British troops, Germans would hold up signs from their trenches, saying 'Irish soldiers! The British are killing your kinsmen in Dublin!' After the war was even more interesting. The Irish soldiers left Ireland as heroes, but came home to find themselves viewed as traitors. Their entire contribution to the war was erased from history. It was really shocking to see that that's how history works.

CD: What sets you off writing?

PM: Hmm. Masochism? I don't know. Sometimes I'll think of a joke, or a couple of jokes. Or a line, or an image, or an idea. You jot down ideas all the time, of course, but once in a while one will come along that's like turning a key, and all of these ancillary ideas come flooding in on top of it. You open your notebook and you just can't write it down fast enough. It's a really exciting process, and you can understand the old concepts of divine inspiration. It really feels like it's coming from somewhere. But that burns out pretty quickly and you're left with the much slower and more prosaic job of trying to tie it all together.

Clare Dudman is the award-winning author of A Place of Meadows and Tall Trees and the 'keeperofthesnails' literary blog