The golden age of detective stories and the locked room puzzle.
Comments about the golden age of detective stories, tell of the domination of Agatha Christie, and before her, Arthur Conan Doyle and even earlier, Edgar Allen Poe. More specifically, the golden age is placed approximately between the two Great world wars, 1920 to 1938.
One particular sub-variant is the locked room mystery. In this, the crime, usually murder, is committed in a way that appears impossible to the reader. Arguably Agatha Christie could be put forward inevitably for her mastery of this genre as well as of her more familiar classics.
I became acquainted with the work of the locked room authors recently through The White Priory Murders by John Dickson Carr writing under the name of Carter Dickson,
and The Moving Toyshop, by Robert Montgomery, writing under the name of Edmund Crispin ...