The basic problem is this: there's too much good stuff.

Let's take a look at some numbers: the American domestic box office was $9.2 billion in 2004 (source: Box Office Guru's Studio Spotlight), 700 million books were sold in the U.S.A. in 2005, 110 million used books resold in 2004 (sources: Book Standard's 2005 Numbers Crunched and BISG Releases Complete Finding from Used-Book Study), and so on, through all of the cultural industries that keep us entertained. It's a vast empire, one that isn't just American, and one that has been going on for a long, long time. It makes me think of that bit of apocrypha that English Lit undergrads pick up: John Milton was the last person who read everything in print, the last person able to do so. In the subsequent centuries, no human being could conceivably read everything new printed in a year, never mind everything in print. Après Milton, le deluge. Just google "too many books" and you'll see that it's a meme that people worry about.

The corollary to the basic problem: there's not enough good stuff.

More properly stated, the corollary is just as paradoxical: it's too hard to find the good stuff. If there are too many books, then why is it so hard to find a worthwhile one to read? It's partly the paradox of choice: as formulated by Barry Schwartz, too much choice leaves you perpetually unsatisfied because there's obviously something better out there somewhere. Conversely, the difficulty is like Sturgeon's Law writ large—with such a vast array of options, sorting out and discarding that 90% of crap is perhaps harder than ever. And by extension, the 10% that might be left over by a diligent researcher's effort is still an overwhelming pile. Finally, it's also the matter of taste: my lifetime 10%, gained by dint of constant striving, might not help you out at all. I like nothing but space opera and you love Tolkien clones to death? Never shall the twain meet.

None of this is new, of course, because we all have strategies for dealing with this. We all pick a new movie to watch or a new book to read based on something, somehow.

Two criteria that come up in the statistics, specifically for books, are word of mouth and cover art. I cop to a growing fascination with the latter—in fact, I'm not sure why succumbing to the lure of fantastic cover art was ever an embarrassing thing, but now I'm firmly in the camp of judging a book by its cover. My time seems more limited than ever, and if your publisher stuck your book with crappy cover art, then tough luck, I'm likely to move on to the next thing.

Word of mouth is a funny thing too. It intersects with personal taste, as mentioned above; if you get a recommendation, you have to trust the other person before you can take the plunge into a new book or movie. And where does word of mouth come from? It's not the same thing as advertising, since by definition there has to be relationship to quality for word to succeed in spreading (whereas with advertising it could be argued that a certain percentage of the time, the hype is trying to cover up deficiency rather than promoting quality). Word of mouth is clearly more powerful, but how often does it actually work? Does it need to work for you in particular or just someone in your artistic vicinity? J. K. Rowling, the face that launched a thousand YA fantasy novels.

These are external factors—relying on recommendations from other people or what the physical copy of a book looks like—but what about internal factors? What about the history of what a reader or viewer has liked in the past? For books, this falls most easily into finding more books by an author a reader has liked before, and within an author's bibliography, reading books in a series. For movies, this might be the same as following a particular actor or actress's career, or a director. As an aside, writers of screenplays seem to get near-zero popular following unless they are someone like Charlie Kaufman (who wrote such genre treats as Being John Malkovich and Eternal Sunshine of the Spotless Mind).

So you could consider a sequel as a shortcut that a reader or viewer takes when confronted with an infinite stack. The brain, instead of utilizing its full potential, short-circuits in a familiar path. Alternately, you could consider sequels as the wisest possible choice. Why not go with the known quantity?

Sequels also interest me in the consideration of their artistic qualities. On the business side of things, they would seem to be the ideal way of building an audience, and for a reader or viewer, they make a heck of a lot of sense, cutting through too much choice. But what about the quality of the product? It's a well-known axiom in Hollywood that sequels have diminishing returns. I think this is partly a product of how hard it is to produce something artistically valid in the first place; if you're creating a sequel, the temptation to toss it off as quickly as possible inevitably comes up. It's easy to think that way.

In the case of a book, I would argue that the most esthetically superior sequel would be one that was just as much work as the original. Just as much blood, sweat, and tears, like the jump from Ender's Game to Speaker for the Dead. Orson Scott Card's two famous books are clearly in the same series, but also just as clearly they are their own unique works of art (Card's Ender series shows up in my taxonomy of sequels below, and not always in a favorable light). What types of sequels do other people find worth reading or watching? Do you write them off categorically? Read nothing else? For myself, it's a case by case basis (however, some of my leanings will be obvious in the framework below).

In sum, it's quite a schizophrenic beast, this business of sequels. For a creative person, the downside would be the difficulty of breaking through the faint expectations for a sequel; the upside is a mirror image, that of breaking through heightened expectations for a sequel. Sequels suck vs. I'm hoping this book will be even more amazing than the last one.

Towards a taxonomy

I'm a librarian by training, and I read a lot of science fiction and fantasy, so my obsessive side (less politely: my nerdy side) often gets a workout. I was contemplating the proliferation of sequels and their ilk—mostly when people argue about this stuff, it's to judge between the items. For example, are sequels written by other people inherently worse than sequels written by the original creator? But any argument needs to have its terms defined.

So here is a taxonomy.

• 1. Sequels.
  • 1.1 By story continuity.
    • 1.1.1 Story line is not complete without subsequent works.

      Most commonly found in a trilogy. J. R. R. Tolkien's ur-trilogy is a bit of a misfit here, considering that he wrote it as a solitary work and it was later split in three. Guy Gavriel Kay's The Sarantine Mosaic is a fine example of duology, while you can take your pick of fantasy series that stretch one story over four or more books.

      As we speak, George R. R. Martin, Robert Jordan, and Steven Erikson are breaking bookshelves worldwide. I see science fiction as less notorious for this than fantasy, although it does happen. Consider Kim Stanley Robinson's Mars trilogy, or even his Three Californias, which were narratively complete on their own but tightly linked on a conceptual level.

    • 1.1.2 Story line is complete. Subsequent works occur in the same universe, perhaps using the same characters, but there's a new crisis.

      Very common. This could include future histories, like Ursula K. Le Guin's Hainish books, or more direct continuations of one person's story, like Richard Morgan's Takeshi Kovacs series. I would probably put the five books of The Hitchhiker's Guide to the Galaxy trilogy here, as well as most sequels in the movies (very few movies leave a story unfinished).

  • 1.2 By chronology (this is arguably a subset of story continuity, but breaks out enough on its own to warrant its own category).
    • 1.2.1 Subsequent books pick up story line immediately after the previous one.

      This happens most often in trilogies, but it also happens to stand-alone books that follow one another (in other words, it could include both 1.1.1 and 1.1.2). Incidentally, the strongest version of this category would be those recent books that have been split in half due to publishing reasons.

    • 1.2.2 A long gap in chronology.

      A perfect example is the expanding gap in Arthur C. Clarke's books: 2001, 2010, 2061, and 3001. It's the same series, but a thousand years have elapsed between the first and fourth books. Sometimes the gap can be shorter. For example, over the course of Jonathan Stroud's excellent Bartimaeus Trilogy, the main character grows from a boy to a young man.

      Two other examples would be the aforementioned Ender novels—Card covers many years because he sends Ender on a slower-than-light trip through space—and Stephen Baxter's Evolution, which has to cover millions of years to live up to its title.

    • 1.2.3 Prequels. Subsequent books take place before events of the original book.

      The mind immediately thinks of Star Wars. That's enough to make me blank out on any other examples.

      As Wikipedia points out, "prequel" is a portmanteau word from the 1970s. And they have a lot of examples over there.

    • 1.2.4 Simultaneous events.

      Much less common, likely because it's difficult to do well. One example is Orson Scott Card's return to the universe of Ender's Game with the sequel Ender's Shadow, which retells the same events from the point of view of a different character.

  • 1.3 By creator's relationship to the work.
    • 1.3.1 Original creator.

      This is usually assumed to be the best case, although not always. Plenty of authors have beat their own series to death, while other writers have kept their artistic integrity in the process.

      As an aside, there are few writers who have not returned to a previous book in some way (at least writers with more than, say, half a dozen books to their credit). Robert Charles Wilson for one. Other examples?

    • 1.3.2 Family of original creator.

      I'm thinking here of the Dune prequels and sequels, written by Brian Herbert along with Kevin J. Anderson.

    • 1.3.3 No relation or for hire.
      • 1.3.3.1 Ghostwriting.

        It's not by the original creator, but the reader doesn't know.

      • 1.3.3.2 Designated in some way by rights holder.

        This would be the vast majority of cases. I'm picturing the multitude of comic books on the shelves—Batman has been around for decades and the sequels are numberless, all authorized by those in control of the copyright.

    • 1.3.4 Sequel to works in the public domain.

      Stephen Baxter's sequel to The Time Machine. I'm also thinking of the more complex case of Alan Moore's The League of Extraordinary Gentlemen, which was a continuation/reworking of half a dozen works in the public domain (it also falls under 3.2.3, below).

• 2. Remakes/Retellings.

  Technically this is a subset of category 3 (Adaptations), but remakes by definition stay in the same medium, so there's no conversion going on. Interestingly, the term "remake" is a pejorative one and applies to the movies, while a "retelling" is an author happily ripping off something like a fairy tale. What's with that?

  • 2.1 By degree of similarity.
    • 2.1.1 The exact same work.

      Very rare—see Gus van Sant's Psycho for my only example. Most people wondered, what's the point?

    • 2.1.2 With noticeable variations.

      This is the most common case. It could be a remake of a foreign film, or a film that is a few years old. It could be something like Margaret Atwood's recent The Penelopiad (itself a contribution to an interesting series retelling old myths) or one of the many Ellen Datlow and Terri Windling fairy-tales-retold anthologies like the recent Swan Sister.

    • 2.1.3 Wildly different.

      The current example that springs to mind is Battlestar Galactica. It's so different than the decades-old TV show, its ostensible template, that fans of the old show felt that it should be titled something else, rather than saddling their favorite franchise with this unrelated junk. I happen to disagree, but I see their point.

• 3. Adaptations.

  Conversions from one medium into another.

  • 3.1 By similarity to source.
    • 3.1.1 Really close.

      The movie versions of Harry Potter and the Sorcerer's Stone or Sin City are most often cited as adaptations that were extremely close to their source materials. To my mind, they were both too close, and didn't take enough advantage of the inherent strengths of the new medium.

    • 3.1.2 Reasonably close.

      Most common. And this makes the most sense to people: a movie isn't the same thing as a book, and shifting things around or leaving out some details is a wise approach. I would say that Peter Jackson's The Lord of the Rings, for all of the warts and offences to fandom, is a shining example of how to not screw things up.

    • 3.1.3 Wacko.

      Technically, Battlestar Galactica could go into this category. A more famous example would be Blade Runner, which ditched a lot of the material from the book it was based on, Philip K. Dick's Do Androids Dream of Electric Sheep?, and even inverted Dick's most plainly argued points from the book. But what a movie! I would tend to judge on an ad hoc basis, rather than categorically say that an adaptation has to be reasonably close to its source.

  • 3.2 By relationship to source.

    This category could go on ad infinitum, so I've kept to the main ones.

    • 3.2.1 Book/comic to movie.

      This is probably the one that springs to mind, although considering the low number of genre movies made per year, it doesn't happen to many books. And it generally does not bode well for the work in question. For every Spider-Man, there's a From Hell or Constantine.

    • 3.2.2 Novelization of movie.

      Every movie has one. They are a strange species, I must say. What is the point? Are they a marketing tool?

      • 3.2.2.1 Crummy novelization.

        Just a depressing make-work project.

      • 3.2.2.2 Unique novelization.

        I can think of two cases, The Abyss and 2001, and these two make the category worth breaking out. In both cases, there was a strong director and a strong writer involved.

    • 3.2.3 Comic of a book/movie/TV show.

      Buffy comes to mind, as there have been numerous comics about the Buffyverse. This would include things like the Illustrated Classics and other stuff for kids.

    • 3.2.4 Book of a radio broadcast.

      The Hitchhiker's Guide to the Galaxy makes this a category all on its own.

    • 3.2.5 Radio broadcast of a book.

      Orson Welles's The War of the Worlds is the biggest example here but others less famous have also been made.

    • 3.2.6 Computer game of an RPG.

      Oh boy, is this ever an overdone category. Thankfully there have been a few original role-playing computer games.

    • 3.2.7 Et cetera.

      As mentioned, this could be a long list. I would also point out that popular stories tend to move through all of the categories until it's sometimes hard to remember where they started.

I'm planning to keep an updated version of this taxonomy on my website. I'll annotate it as I get suggestions, so please let me know about any gaps that you notice.