Easier - A mystery is something that is difficult to explain or understand. Mysteries are also stories where a problem, crime, or puzzle must be solved. Harder - Mysteries often contain secrets or hidden qualities that must be solved. There may be information that is unknown and must be explained. Professional detectives and sleuths seek out clues to solve mysteries. To solve a mystery, people must use their skills at deductive reasoning. Mysteries are a popular genre of fiction. Many people enjoy reading series of books by the same author. For example, Sherlock Holmes is a classic fictional sleuth.