Stabber McBitchface on the lipstick planet! Not really. Wiki: "The book's plot takes place in the years 1988–1989 in a timeline where the Spanish Armada under the command of the Duke of Parma successfully invaded England in 1588."
So it's a time-travel / alternate timeline novel. Wiki says most of his books were out of print when he died in 1995. The cover couldn't have helped matters.