Do spy novels come under Mystery ? They do have the same whodunit/detection thing except on a larger scale.
Is it possible that the Mystery novel (such as Christie and Doyle) got replaced by spy novels in the 80's. In my time, Alistair MacLean was a hot author (usually kids graduated from Hardy Boys to MacLean). "Fear is the Key" was the hot title. Then Sidney Sheldon etc became popular. I liked Tom Clancy and the spy theme.
After the breakup of Russia, the spy novel (and 007) moved onto North Korea which became very dull.
Happy New Year, trolls.