Nobody shouts "It's alive!" in the novel that gave birth to Frankenstein's monster. "Frankenstein, or the Modern Prometheus," does not feature mad scientists messing around with beakers in laboratories, nor does it deliver any bug-eyed assistants named Igor. Hollywood has given people those stock images, but the story of the monster and his maker owes its essential power to the imagination of an 18-year-old woman and the waking nightmare she had by the shores of Lake Geneva one rainy summer almost 200 years ago. If, that is, one believes that Mary Wollstonecraft Shelley really was the genius behind one of the most enduring tales of existential horror. Almost from the moment that it was published anonymously on New Year's Day 1818, "Frankenstein" had readers and critics arguing over its origins. Early rumor held that it wasn't Mary Shelley, but her husband, the Romantic poet Percy Bysshe Shelley, who deserved the credit. (Or the blame; some early readers were outraged by the novel's idea that a man could play God and create life.) This article reports on a new edition of the novel which sheds light on the Shelleys' collaborative relationship.