Much like a mystery novel, a "cozy" mystery includes an amateur sleuth and a crime, but with "cozier" storytelling. The cozy mystery sub-genre started in the 1920's with the world's most bestselling author Agatha Christie and has been represented in television shows like Murder She Wrote. As award-winning author Nancy J. Cohen explains, a cozy mystery differs from a standard mystery in that it excludes sex, graphic violence, and bad language. The stories are clean and the genre has a loyal following of readers that appreciate the lighthearted approach. The keys to a good cozy mystery, Cohen says, are an intriguing main character with an interesting occupation and the interrelationships between the group of suspects. Cozy mysteries also tend to include some humor and romance. Cohen, who is working on her fifteenth book in her popular Bad Hair Day Mystery series, enjoys writing in this genre and aims to provide an escape for her readers.