The credits for the film "Young Frankenstein" say it is based on "Frankenstein" by Mary Shelley.
But in fact, the film is actually based on previous films, not on the novel.
In particular it is very much, and appropriately so, based on "Son of Frankenstein" by Wyllis Cooper.
For example, these could hardly be coincidence:
- The hunchback playing a horn on the rooftop.
- The huge knockers.
- The walk-in fireplace.
- The police inspector's:
- false arm that needs to be moved by the other arm.
- using false arm as a temporary place to stick darts.
"Young Frankenstein" is almost a remake of "Son of Frankenstein", but the film gives no official credit at all to where they copied their material from.
Is there no legal obligation to give credit where it is due?
Note that I'm not asking for interviews etc. where people say it was based on the other movies; I'm asking about the official credits themselves.