The son of a physicist, he was brought up from the age of seven in Lisburn, Northern Ireland, where he attended the Friends' School and was taught by James Simmons.
After publishing his first novel, a Sherlock Holmes pastiche, he lived for four years in Italy, teaching at the university in Perugia.
This series of detective novels provide a penetrating insight into the less visible aspects of Italian society over the last 20 years.
The character of Zen himself is anti-heroic, which adds much to the books' irony and black humour.
A final Zen book, End Games, appeared posthumously in July 2007.