The novel "Frankenstein; or, The Modern Prometheus" was written by English author Mary Shelley. She began writing it when she was 18 years old, and it was first published anonymously in 1818. Mary Shelley wrote the story about Victor Frankenstein, a young scientist who creates a sapient creature in an unorthodox scientific experiment. The name Frankenstein is often mistakenly used to refer to the creature, but it is actually the name of the scientist who made it. The creation of the story was inspired by a writing competition between Mary Shelley, Percy Bysshe Shelley, Lord Byron, and John Polidori, and was influenced by themes like ambition, science, and the Romantic movement.