To me there are two kinds of series:

Playground Slide Nice climb in action, lots of thrilling fun going down, but you're back where you started. This sort of series has a long, honorable, and successful tradition behind it (Sherlock Holmes stories, Star Trek, even The Simpsons). Yes, the characters can come out of it a little wiser. Even Holmes changed his opinion of women after his encounter with Irene Adler in A Scandal in Bohemia, and Watson gets him to cut down on the liquid cocaine, but we want the story to begin on a dreary morning at 221B Baker with Holmes lecturing Watson on the dearth of imaginative crime or it just seems wrong. My least favorite ACD stories involve Holmes as a beekeeper in the South Downs or Watson chained to one of his soon-to-succumb-to-necessity wives.

There's nothing wrong with writing this kind of series. They're like comfort food. In a way, this takes more talent to do well, because the audience has to to buy the characters never changing despite what they go through (what keeps Marshal Dillon from marrying Miss Kitty, who's not a prostitute in any way whatsoever, nosiree Bob, despite their obvious fondness for each other?). In fact, because you've created something so delightful, the audience will throw a fit if they change. But there are a lot of pitfalls. That your fiction becomes just plain boring is one of the bigger ones. Or that you'll get sick of doing the same thing over and over, like ACD. But damn, when it's good, it's great, like a wonderful evening with old friends. Didn't the best episodes of the X-Files mostly involve Mulder and Scully outside the big alien conspiracy story arc?

Staircase You're somewhere else after the story climb. For me, these are a little more interesting to write and read, as each time the character's starting point is different from the last and the circumference of your world changes. A good example is the Hornblower books. Horatio is the same capable, dutiful officer, but he grows in responsibility, from being in charge of a jolly boat as a midshipman to commanding an entire fleet in the Caribbean, so you get to see him applying his talents in different ways.

I think Star Trek: Voyager would have been more of a storytelling success if it had, after a season or two of them trying to get back and realizing it was futile, borrowed a few pages out of The Aeneid and had them give up and form a new Federation out in Delta Quadrant. It probably would have failed, since Star Trek fans expect a playground slide, and a switch to a staircase wouldn't have meant a seven-season run, even with Jeri Ryan's tits. But it would have failed while daring greatly.

Of course there are quasi-series authors who produce similarly-flavored books over and over and over again. Playground Slide? I think so. There are hugely talented people in this category, like Louis L'Amour, whose heroes vary in exterior features, but inside it's the same guy. Not that there's anything wrong with stories built around characters with virtues you admire. You're writing from the heart that way, and your books are better for it.

After a few books you get branded, for good or ill, and your audience knows what to expect. You've got the handcuffs on, you just have to hope they're golden on the inside.

Cheer up, there are always pseudonyms.

Most of the guff I get from people who are unhappy with my books boils down to "this one wasn't like the last", or like their favorite (Cat, by most accounts, with Rising running a close second so I guess suricattus takes the editorial trophy by a half-length). They want the Playground Slide. If, that is, they were ever impressed with my storytelling in the first place. I get plenty of well-evidenced email pointing out that I've always sucked from the first couple chapters of Wolf.

I totally understand the impulse. (To want the same reading experience, not to tell me in detail how I waste trees.) If I'm in the mood for a Retief story, I want him stuck in a low-level position in the CDT, snared in red-tap, with blundering superiors and ill-intentioned Groaci or Hattracks threatening Terra's place in the galaxy.

Maybe someday I'll do a Playground Slide series. It's just not in me now. I wouldn't mind at all if I found my ideal niche, and, Louis L'Amour style, wore my golden handcuffs with dignity and put out a book or two every year that delights an audience seeking my particular flavor of storytelling. But Stella hasn't quite found his groove yet.

Is there a point to this post for aspiring writers? Ummm, no, except if you want to do a popular fiction series, you pays your money and you takes your choice. I just want to help you choose wisely.