In The Guardian Mark Lawson profiles Andrea Camilleri: a life in writing -- and you have to like his approach to finishing off his Montalbano-series:
I finished him off five years ago. That's to say, the final novel in the series of Montalbano is already written and deposited at the publishing house. When I get fed up with him or am not able to write any more, I'll tell the publisher: publish that book.