Was it one of my ghost stories, on which my reputation as a writer was established? No.
Was it one of my top selling Forgestriker series? No.
The book which made the sale is the fictional account of a rescue by a lifeboat crew
http s://www.draft2digital.com/book/45659 a rescue I know happened. One of my uncles was involved in the rescue, and I have a copy of the newspaper showing the crew being awarded the Gold Medal for bravery.