The "Golden Age of Detective Fiction" refers to a period primarily between the 1920s and 1930s when mystery novels flourished. This era is characterized by the rise of amateur sleuths and intricate plots, often featuring a closed circle of suspects. Prominent authors like Agatha Christie and Arthur Conan Doyle became widely popular, creating iconic characters such as Hercule Poirot and Sherlock Holmes. During this time, detective fiction emphasized logical reasoning and fair play, allowing readers to solve the mystery alongside the detective. The genre's conventions, including the use of red herrings and twist endings, became staples that influenced future works. This period laid the foundation for modern mystery writing.