A hexalogy (from Greek exa-hexa-, "six," and -logia-logia, "discourse") is a literary or narrative work composed of six separate works. The term was coined by the German scholar Hermann von Soden in 1877. A hexalogy is different from other forms of multigenre fiction because it cannot be interpreted as one story with multiple parts. Rather, it consists of several independent stories that together make up the whole. Each part contains an individual plot with its own beginning and end; however, the parts also relate to each other through common characters, settings, and themes. Hexalogies are usually published in book form but can also be presented in audio or video formats. Hexalogies are commonly used in art books and magazines. For example, American magazine Rolling Stone has published a serialized novel written by J. K. Rowling under the title Harry Potter and the Philosopher's Stone since 31 August 1997. It is divided into six parts which are titled "Prisoner of Azkaban", "Goblet of Fire", "Chamber of Secrets", "Crucio!", "Poison Ivy". Each part contains a complete chapter of about 15 pages. The entire novel has a total length of 155 chapters (5020 pages).