The Invisible Man stars Claude Rains, a big favorite here. We've watched him recently in Mr. Smith Goes to Washington and The Wolf Man.
Dwight Frye (Frankenstein, The Vampire Bat, Dracula) has a cameo as a reporter. Henry Travers (High Sierra and as Clarence the angel in It's a Wonderful Life) plays the scientist who supervises Claude Rains' character.
This was the first time the Younger Son had seen this movie.
It's available at Youtube, but embedding is disabled.
10/31/2008: The Younger Son picked this one to watch tonight.
1000 Misspent Hours calls this "one of the best horror films of the 1930’s" and calls the special effects "absolutely groundbreaking". Moria says this film "is one of the few times when a film actually improves upon a book" and believes it is director James Whale's (Frankenstein, Bride of Frankenstein) "undeclared masterpiece". Moria adds that it may have "the best dialogue to ever grace an sf film".