Frankenstein by Mary Shelley
Mary Shelley was arguably the first female science fiction writer, and her novel is one of the most influential ever written in any genre. Frankenstein; or, The Modern Prometheus, is a classic story that just about everybody knows: Victor Frankenstein creates a rather grotesque man in a science experiment, effectively playing god himself. Naturally, the results are less than awesome for Dr. Frankenstein.
Scare Factor: 2 - More sad than genuinely scary, but a brilliantly told story nonetheless.