The title's inclusion of the phrase "The Modern Prometheus" tells the reader before they even crack the spine of the book that this is a tale of a character taking something that is not theirs to take and consequently being brutally and eternally punished. This addition to the title is an allusion to mythology in which a human man, Prometheus, managed to steal the secret of fire (and thus also the power of withholding) from the gods and distribute the information to man. As punishment for his crime, Zeus sentenced Prometheus to be tied between two trees, naked, for the rest of eternity while a giant bird of prey came every day to eat the liver out of his living body. Over night, his body would heal and every day he would be subjected to the same torture.
This tells us that Frankenstein, having taken something that was not his to take (the secret of creating life), will be punished in the end for his presumption, insolence, and irresponsibility. His punishment is not handed down by the gods, though. It is put into action through the product of the crime - the Creature.