The series has become popular for readers, authors, and publishers, for different reasons. Readers want to continue dwelling in a particular world, like Middle Earth, or want to continue following the quests of particular characters, such as Harry Potter. By contrast, authors enjoy expanding upon worlds they have already created, frequently making the writing of multiple books easier; they do not have to reinvent that world for each book. Publishers desire a series because it frequently translates into more book sales. One reader buys all the books in the series rather than just one book. This article defines a series and what binds the individual books together.
A series is a collection of books. To be a series, technically speaking, the collection must be more than five books. Naturally, one book cannot be a series. Two books is a duology, and three books a trilogy. Four books are termed a tetralogy, and five books a pentalogy. Although there is some disagreement over these terms, a “series” for purposes of this article refers to multiple books.
In a series, the books must have something connecting them, otherwise the books are simply independent. One connection is a cast of characters found in all the books. For example, book one could introduce a family of eight. Each subsequent book is primarily about one family member and only secondarily about the other family members. That cast of characters could also be a group of friends or group of co-workers or some hybrid of family, friends, and coworkers. Another connection is a location. For instance, a hotel. The first book could be about the clerk at the front desk. The second could be about a person working for housekeeping, and the following books might focus on various hotel guests. The cast might be different in each book, but the setting or location of every book remains the same: the hotel.
Another connection for books in a series can be the plot. The series could be about serial killers, where each book is dedicated to one serial killer. Or the series could be about treasure hunts, where individual books are about individual hunts. Notice that the location would be different in each book and so would the cast. Of course, the connection can involve more than one of these elements of plot, location, and character. A book series could have all three elements. For example, two teenage boys live in a small town, and they solve crimes. In every book, the protagonists are the two boys (characters), solving a specific crime (plot), around town (location). What might distinguish a series, however, is to find other forms of connection beyond these common overlaps of plot, location, and characters. What other story elements can serve as the thread through each book in a series?