Step 1 : Introduction to the question "Which beloved fictional detective appeared in 12 novels written by Agatha Christie?"
...Miss Marple, the sharp-minded and keenly observant elderly sleuth from the quiet English village of St. Mary Mead, appears in 12 full-length novels by Agatha Christie, beginning with The Murder at the Vicarage (1930). Unlike the more flamboyant Hercule Poirot, Miss Marple relies on her deep understanding of human nature and subtle village parallels to solve even complex crimes. In addition to her 12 novels, she also appears in numerous memorable short stories, solidifying her place as one of Christie’s most enduring and beloved characters.