A book series might be as little as two novels or as much as 50 books and counting. It all depends on the sort of narrative you're telling and how long you take to tell it. The number of books in a series is called the series length. In television, film, and comics, there are often multiple stories that use elements from within one overall story arc. Each chapter or episode of this type of work can be considered its own novel or movie, respectively, and usually follows its own unique plotline that has nothing to do with any other story within the collection of films or books. However, in literature and journalism, a series is defined by the publisher as being three or more books that share a common character, setting, or theme. This type of series allows for greater flexibility in storytelling because the author or authors can explore different characters, settings, or themes within each individual work rather than being limited to one aspect of life during each successive installment. For example, one writer might focus on a single character over several books while another writer might explore different characters in each of their works. Still others might choose to set their novels in one location and later move to another. Whatever the case may be, writers have great freedom in choosing what kind of series they want to publish based on themselves or their editor's needs.