I've been researching horror films of the 30s and 40s lately for a writing project, and I have to say, I am deeply disappointed in the professional literature and in the fandom writings.
Simply put, there are approximately FIFTY Universal Horror films from those years (give or take some that might be categorized into other genres). Yet almost all of the books or websites or documentaries act as if there are JUST the main ones, and even then they often ignore or gloss over the sequals.
They ignore the existence of over half of these great films. They usually skip over any mention of actress Evelyn Ankers (in eight movies) or the "Paula the Ape Woman" films (she had three movies, more than Wolfman).
I mean, Star Wars fandom has disected every frame of every movie, but nobody has a paragraph to spare for "She Wolf of London?"