There are few more seductive figures for biographers than Mary Shelley. The daughter of the radical philosopher and novelist William Godwin and the great feminist thinker Mary Wollstonecraft (who died a few days after giving birth to her), she ran away with the poet Percy Bysshe Shelley at 16; wandered through Europe with him; bore their four children; married him; became the friend and companion of the other Young Romantics and their lovers; and at 18 wrote the classic Gothic novel Frankenstein, or The Modern Prometheus.