Recently I read, back to back, two books that incorporated multiple characters. I don't mean a handful, but literally dozens of people, who played varying roles in the story. I thought in one case it worked well; in the other, not so much. And I've been trying to figure out why.
These are both cozies, by writers who have written other books in the same series. I've read the other books, and I know and like both authors. I'm not going to name names, because I'm not promoting or slamming either author. I just want to come to terms in my own mind why one treatment was more successful than the other.
Cozies by definition take place within a closed community, which means that the villain can't be a stranger who wanders into town and commits a crime, unless that stranger is one of the existing character's Uncle Fred or Aunt Tillie, come back after plastic surgery to reclaim the stolen inheritance. The rules say there has to be a connection to the town, however obscure, because how else can the protagonist talk to people in town and gather clues?
What size is a small town? Two hundred people? Two thousand? And how many of those people does the protagonist know by name, or know well enough to call by his or her first name? I haven't done any scientific analysis, but I'd guess the pool may be, oh, twenty people? And generally, in a series, these people are introduced gradually, a few per book, and they'll return in future books in the series so the reader can get to know them and remember them. If you the writer are lucky, your readers will contact you and ask, "when will we see So-and-So again?" Which tells you that you've created a memorable and likeable character.
So what went right and wrong in the two books I mentioned? That's what I'm puzzling over.
--Was the cast of dozens organic and relevant to the plot (i.e., did those people have a reason to be there)? Yes, in both cases. In one, it was an unusual situation, but logical; in the other, it was small-town business as usual.
--Did the characters have enough "face time" for us to get to know them? Not so clear. I don't know if there's a standard for word count to establish personality, but in one book the characters distinguished themselves quickly--their own identities, and their relationships to each other. In the other book, there were a lot of people who popped up now and then, and usually the first time they were accompanied by a tag-line explaining them ("Suzie, my former best friend from high school, who had been going through a rough patch with her third husband and was currently living off handouts from her redneck relatives"). The latter smacks of the dreaded "telling, not showing."
I'll be the first to admit that it's not easy to throw in a new character without adding an explanation. It's a challenge to give them a real personality with only a few lines of dialogue and some brief indications of body language. Sure, you can use some description occasionally, but if you add it to each new character, it quickly becomes repetitive and throws you right out of the story.
Back in the golden age (whenever that was), mysteries, particularly British ones, used to include casts of characters right up front, along with maps of the small town and diagrams of the manor house where all the action takes place. The character list was often quite detailed: "Sophronia Everlast, the maiden aunt of Hector Pumphrey, lord of the manor;" or "Tilly, the second chambermaid for the South Wing." It seems quaint now, but if you were reading the book intermittently and managed to forget who was who, it was nice to have a reference handy.
I don't think readers' attention span has improved. Nowadays we're used to quick snapshots of information, and we're often doing two or three things at once. We're not necessarily as able to focus and concentrate on a book, much less keep track of who's who.
Does that mean we the writers have to dumb down our stories? Limit the number of cast members? I hope not. But we do have to be careful not to overload the cast. Okay, the shopkeeper down the street is a lovely person, but couldn't that important clue be delivered by someone else we've already met?
I'd hate to reduce writing in any genre to a formula, but how many characters in a book is too many?