The book is sort of a parable on child abandonment. Frankenstein creates a life with no regard for the consequences and then runs away from it. The creature becomes a monster because of the way it is mistreated. The book is oddly structured in the way of some 19th century novels. At one point the narrative is three steps removed as the monster tells his story to Frankenstein, Frankenstein tells the story to the ship captain, and the captain tells the story in a letter to his sister. If all you know about the story of Frankenstein is from the movies just wait until the monster starts quoting Milton's Paradise Lost.