A few films with libraries are sketchy for me, but I seem to recall a
scene from INDIANA JONES AND THE LAST CRUSADE with a trap door in a
libray (and a librarian making really loud stamping noises, or was that
another film?...)  Also, some home libraries--old Howard Hawks Film
called BALL OF FIRE with a bunch of old men doing research for an
encyclopedia.
 
Recently, scene in FOREVER YOUNG with Mel Gibson in a library with a
kid;  There's the school library setting of THE BREAKFAST CLUB;  The
German film THE NASTY GIRL has some important library scenes.
 
I know there are others (I can picture some but can't remember anything
about them)...
 
Amanda Aaron