What is the main idea of the introduction to Frankenstein

The idea for Frankenstein comes to Mary Shelley as a series of terrifying images after she overhears a discussion about reanimation. Mary Shelley made an anonymous but powerful debut into the world of literature when Frankenstein was published in March 1818. She was nineteen years old when she began writing her story. One night Mary Shelley imagined the "hideous phantasm of man" who became the deeply sensitive creature in Frankenstein. The novel combines, for example, themes of nature versus nature, good versus evil, and ambition versus social responsibility dominate readers' attention.