For movies with librarians (of course you've got Marian the Librarian
from MUSIC MAN (!?), how about
IT'S A WONDERFUL LIFE . . . in the what-if sequence, when George Bailey
gets a chance to see what his town would be like if he'd never been
born, he discovers that his wife Mary would have turned out to be,
instead of a wife and mother, a . . . . librarian! = frightened old maid.