Medieval literature
Some authors make it difficult to list their books in a numerical order when they do not release each work in its 'proper' order by the story's internal chronology. They might 'jump' back in time to early adventures of the characters, writing works that must be placed before or between previously published works. Thus, the books in a series are sometimes enumerated according to the internal chronology rather than in publication order, depending on the intended purpose for the list. Examples of this series include works from the "Chronicles of Narnia", where the fifth book published, "The Horse and His Boy", is actually set during the time of the first book, and the sixth book published, "The Magician's Nephew" is actually set long before the first book. This was done intentionally by C. S. Lewis, a scholar of medieval literature. Medieval literature did not always tell a story chronologically.