Series give great benefits to readers: they can return to a world which they enjoyed, and satisfy their continuing curiosity about beloved characters. Writers benefit, too: they don't have to start from the creativity process from scratch, and book two may be easier to sell than book one. Publishers are also happy in being able to make an easy decision about which book to publish -- the one that already has an established audience, of course -- and rake in the spoils. So, a successful series is worthwhile, for all parties concerned. But it's an enormous task, with special pitfalls that happen only when writing a set of interlocking books. Before you embark on the greatest of marathon writing projects, you should be aware of the challenges that make a series of books more difficult than stand-alone projects.

Challenge # 1: The story takes a long time to complete

With a story spanning several books, there is always the possibility that the readers or even the authors may never get there. Real life intervenes. Twelve years passed between Jean Auel's publication of The Plains of Passage and The Shelters of Stone.

Decades went by between the third and fourth books of Asimov's Foundation series. Would-be authors should ask themselves if they have the interest and the stamina for such a long journey.

Challenge #2: The books mean a more constrained universe for creativity

One of the biggest challenges is that the author, in book two, must live with the consequences of the book one. It may mean having to do without a character that the author killed -- although some authors get around this by bringing characters back. For example, Tolkien brought Gandalf back in book two of Lord of the Rings, although one could characterize Gandalf as "missing in action, presumed dead" after his disappearance in the first volume.

Challenge #3: The author has to remember many details

An interlocking series means a complicated journey, and the author needs to remember many details or face being scolded for self-contradiction. Changed spelling and changed attitudes are reasons for some fans' dissatisfaction with Jean Auel's latest book. Other series approach this pitfall differently. Instead of making the stories interlocking, they have the same characters without a real continuation of the plot. Many detective series are like this. (Agatha Christie's Hercule Poirot and Jane Marple, for example; although there is some continuity, if you come up with reasonable estimates of their ages at the beginning, they would have to be centenarians by the last book. Or, Carolyn Keene's Nancy Drew, who, at least when I was reading them, was forever eighteen.) A series may be constructed even more loosely and be either a return to the same universe but without necessarily the same protagonists (Anne McCaffery's Dragonriders series) or even simply moving on to descendants and successors (Colleen McCullough's Masters of Rome and Noah Gordon's Physician series).

Challenge #4: Each book should stand on its own

Face it, some books don't stand alone. For example, Tolkien's The Fellowship of the Ring, the first book in the trilogy The Lord of the Rings, really does not work by itself. Fortunately during the latest filming of it, the producers made all three parts together, so that the moviegoers would not be faced with an incomplete product.

Other books, even when they leave some issues unresolved, manage to give the reader a sense of completion at the end of each volume. J.K. Rowling does this with the Harry Potter books by having Potter and his friends achieve a difficult task in every volume. Even though the danger still lurks, our heroes have triumphed for the time and can breathe more easily. She also concludes each volume by sending Harry home to Privet Drive at the end of each instalment. Harry is on summer vacation, which means a holiday for everyone, including Ms. Rowling.

Challenge #5: The same but different

One of the most challenging aspects to writing a series is keeping the interest of the readers from one book to the next. The author scored a hit with book one; what does he do in book two? If he uses the same formula as in book one, some readers will complain that it's too similar to book one. If he strays from that formula, other readers will complain that the book is too different. As readers have different tastes in this regard, authors will likely not please everyone.

The author has a particular challenge when following the same protagonist from one volume to the next. If the main character has fallen in love and gotten married -- something which happens at the end of many books -- then the marriage, the consummation of a relationship, can't happen again in the next without undoing the ending of the previous story.

If the hero has learned and mastered all challenges by the end of book three, what remains of interest for volume four?

J.K. Rowling has her own technique for the same but different conundrum. Each volume follows a single school year at Hogwarts, giving each book the same setting and much of the same structure. But in each successive book Harry Potter is a year older, with more mature concerns and greater challenges in the battle between good and evil.

Challenge #6: What to do with back history

If the author has a devoted following, another big question is the back story. When writing book four, should the author assume that the readers are intimately familiar with books one through three? How much rehashing should the author do? Will repetition of previous information bore faithful readers? Will lack of the information confuse the newcomers?

Again, this is a situation where the author probably won't be able to please everyone. In the second Harry Potter book, J.K. Rowling faced the problem that not all of her readers would understand Quidditch, the game played on broomsticks. But Harry, as one of the players, did not need to relearn the game himself. Rowling solved this problem by having Harry explain the rules of the game to a new student.

Challenge #7: More issues to resolve

This can be a plus and a minus. The writer who has more things to write about is less likely to suffer from writer's block. And the readers can content themselves with more story. Still, the books can grow longer and longer.

One reason the Harry Potter books became more and more voluminous as they progressed was simply because there was more story to tell, more characters to catch up on from one book to the next. Even bit characters needed a few words so that their development could continue.

What Price Success?

Many series are "successful" without dealing successfully with all these elements -- that is to say, the series are financial successes. But some of the readers will be disappointed; they will complain that they have been betrayed by the author and the publisher and that the standards have been lowered to make more money.

Making more money is an understandable goal. Still, it should be possible, though not easy, to have a successful series which continues to please readers -- more of the readers, anyway -- by meeting the challenges above. Before you decide to go to distance, consider the difficulties, and how to overcome them.

Find Out More...

• Lynn Flewelling: Writing the World of the Series, by Moira Allen
  
  
• Planning the Series Novel, by Vickie Britton and Loretta
  
  
• The Stuff Series Are Made Of, by Karen Wiesner