When after reading and posting about The Death List I went to Paul Johnston's website I was impressed by both his honesty, his sense of humour, and the fact that he was questioning through Matt the morality of his profession.
"Another area I wanted to investigate was the relationship crime novelists have with their material. It's often curiously hands-off. The closest most of us come to illegal acts is parking with a wheel on the kerb. I wanted Matt to experience the reality of murder (notice that I put my fictional character through the meat-grinder rather than courting danger myself - typical author…). He is forced to question the morality of his profession - something that I don't think all crime novelists do.
For what it's worth, my opinion is that reading and writing about awful acts are worthwhile activities because they put us in extreme situations and make us wonder how we would cope - not least, how we will cope with death, something we're all going to face sooner or later. Whoah, this is getting a bit heavy…
The fun side of the book, at least from the writer's point of view, was making use of Jacobean revenge tragedies. Plays like Webster's White Devil are seriously over the top - and this stuff was acted in front of people, rather than re-enacted in the reader's mind. A few crimewriters have made references to the genre (for instance, P. D. James's novel The Skull Beneath The Skin), but I'm amazed its similarities to the modern crime novel haven't been explored more. Too late, the rest of you scribblers. I've beaten you to it…"
from www.paul-johnston.co.uk where you can find a wealth of information and a long interview with the author