" It was really in the Golden Age, between the two world wars, when the pure detective story – of which the locked room mystery is really the ultimate form – became popular. "
- Otto Penzler

In the era often referred to as the Golden Age—specifically between the two World Wars—a particular type of storytelling gained significant popularity among readers and writers alike: the pure detective story, with a special focus on the locked room mystery. This narrative form captivated audiences due to its intricate plots and surprising resolutions.

The quote highlights an interesting period in literary history when societal conditions contributed to a surge in interest for complex and intellectually stimulating literature like detective stories. The term "pure" here suggests that these narratives were characterized by their adherence to specific conventions, such as logical puzzles and careful plotting without extraneous elements. Moreover, the locked room mystery—a subset of this genre—represents the apex of these qualities because it presents readers with a seemingly unsolvable scenario, which then must be unraveled through clever detective work. This form not only entertained but also engaged the intellect of its audience during a time of relative peace between global conflicts.

Otto Penzler is a well-known figure in the world of crime and mystery literature. As an editor and publisher, he has made significant contributions to preserving and promoting classic detective stories. His expertise and deep understanding of this genre make his observations on the evolution and popularity of different narrative styles highly insightful for both scholars and enthusiasts interested in the history and development of detective fiction.