This is not a post wrought through white-hot fury and righteous anger. Sorry. Sometimes I just have a specific heading on my mind that I can’t cram into 140 characters.
Detective and mystery stories has a UF of Detectives—Fiction. This is a problem.
Remember our good friend LCGFT? Of course you do. Well it didn’t always exist, and even once it DID exist, literary terms were only added recently.
So here’s the thing, back in the day pre-LCGFT — we were sloppier about mixing our genres/forms and our subjects. So if you assigned a Sherlock Holmes story:
650 _ 0 Detectives and mystery stories
(Or more likely, Detective and mystery stories, English — but now I’m quibbling)
It was correct.
But nowadays we are more careful and thoughtful about this mixing.
Subjects (650s) ought to be for what the resource is about.
Genre/forms (655s) are for what the resource is.
A Sherlock Holmes story isn’t about ‘Detective and mystery stories’, it’s about speckled bands, blue carbuncles, or evil mormons.
(Seriously, have you read Study in Scarlet?!)
Anyway — those are subjects, and then for form, we’d look to LCGFT and find:
Detective and mystery fiction
So today, a good array of headings might be:
650 _ 0 Detectives $v Fiction.
650 _ 0 Carbuncles $z Goose $v Fiction.
655 _ _ Detective and mystery fiction.
But then you go and control them — and SNAP! That first one becomes Detective and mystery stories, ruining your perfect array.
Now my understanding is that as LCGFT grows in use and acceptance that the subfield v terms will be phased out entirely of LCSH, but until that happens we need to watch out for UFs like this that convert a Subject–Form string into one that is purely form.