A detective story, also known as a whodunnit, is a genre of fiction in which a detective investigates and solves a MYSTERY. It typically involves a mysterious crime, such as a murder, and the detective's efforts to uncover the perpetrator. The term 'whodunnit' is derived from the question 'who done it?' which is often asked by the detective in the story. A MYSTERY is a story in which the reader is presented with a puzzle that needs to be solved. The reader is usually given clues throughout the story that help them to solve the MYSTERY. The term 'whodunnit' is often used interchangeably with 'MYSTERY' to refer to this type of story.