Jack Murphy passed along to me this article from the fantasy literature website Black Gate. It is a discussion of the nature of "serial fiction", and it is pretty thought-provoking.
My biggest quibble with the article is that, like so many literary theorists and critics, the author spends what seems to me like an inordinate amount of time trying to pin down exactly what should be considered "serial fiction", but in the process, he seems to step on his own toes a few too many times. Apparently short mini-series comics aren't serials, and perpetual titles like Spider Man aren't serials, but the 75-issue Sandman series is, as is the 300-issue Cerberus. I guess his definition of a serial is that it has to have a definite beginning and an end, with a story arc that encompasses the whole, but with individual arcs that make up the installments.
To me, this makes sense, but I think it should be a little more open to interpretation. Was The X-Files a serial television show? It had an arc of sorts that it was trying to tell, but many episodes (the "creature features") had nothing to do with that overall arc. The original Star Trek could also be considered a serial, as the crew of the Enterprise was on a "five-year mission", but almost no episodes of the show weave together into any kind of over-arching plotline. Is the old 1930's Buster Crabb Flash Gordon a serial? It certainly seems like it should be. I think the sci-fi spy series Alias and the newer series Lost are excellent examples of modern serial stories on television, but what about shows like The Wire? Each season has an arc, and the seasons interconnect in various ways, but I'm not sure that story could ever "end" like a serial should.
And what about historical fiction? Bernard Cornwell's Richard Sharpe novels, set in the Napoleonic War, by default have a beginning and an end - the Napoleonic War itself. But Cornwell then expanded the series with prequels and at least one "sequel", so does that change the original Peninsular Campaign novels from "serial fiction" to something else? Likewise, what about Patrick O'Brian's naval adventures? You could write a series of novels about a historical event knowing that the event does, eventually, come to an end - is that the "end" of the arc, or is the arc something more abstract? Is it the journey the character goes through, such as in stories like HBO's Band of Brothers or The Pacific? Each of those has a historic start and end, but also follows arcs in the development of the people involved.
I refer to book series like The Executioner and The Death Merchant as "serial action adventure fiction" because they are simply a series of interconnected novels. You could say Pendleton's original 38 "War Against the Mafia" novels are a "serial fiction" story, but then the later 300+ novels are just barely related episodic stories. In my mind, any series of novels written from the beginning with a numbering scheme feels to me in some way as "serial fiction"; after all, don't these books have "serial numbers" on them?
Anyway, much food for thought.