PLAGARIZED From 'The Curse of The Werewolf' (Spoilers)
Points of Similarities
1) Man is chained up in basement
2) Man becomes an inhuman beast after years of captivity
3) The beast rapes a woman than dies
4) The woman is impregnated
5) The woman gives birth to a son
6) Upon maturity the boy starts to transform into a monster
7) The monster is destroyed by his adoptive father.
IT looks as if the book 'The Beast Within' was ripped off from either the Hammer film 'Curse of the Werewolf' or the story that it was based on.