As I'm not aware of John Cornwell's first fiction novel, in general, a first novel might introduce unique characters and settings that the author has been incubating for a long time. It could also have a rawness and freshness that subsequent works might refine. Maybe it has an experimental plot structure or a very personal theme that the author was eager to explore at the start of their writing career.
I don't have enough information about John Cornwell's first fiction novel off - hand. However, you could try looking on book review websites or asking in book - related forums. They might be able to point you in the right direction.
Patricia Cornwell's first novel is 'Postmortem'. It's a great mystery novel that features Dr. Kay Scarpetta. The story is filled with suspense as she delves into forensic investigations to solve crimes. It's well - written and has elements that keep readers on the edge of their seats, like the complex web of clues and the dark secrets that are gradually uncovered.