Good vs. evil is basically the novel’s biggest theme. More specifically, Dr. Jekyll and Mr. Hyde is easily viewed as an allegory about the good and evil that exist in all men, and about our struggle with these two sides of the human personality. In this book, then, the battle between good and evil rages within the individual. The question is which is superior. Since Hyde seems to be taking over, one could argue that evil is stronger than good. However, Hyde does end up dead at the end of the story, perhaps suggesting a weakness or failure of evil. The big question, of course, is whether or not good can be separated from evil, or whether the two are forever intertwined.
The relationship between Dr. Jekyll and Mr. Hyde begins as father/son then shifts to that of equals vying determinedly for dominance.