https://standardebooks.org/ebooks/mary-shelley/frankenstein
Sharing another book that is free to download and own, depending on your local public domain laws. Enjoy!
"Mary Shelley (then Godwin) and Percy Bysshe Shelley were visiting their friend Lord Byron in Geneva one rainy summer. With the weather against them, they decided to spend their time writing ghost stories for each other. Frankenstein is Mary Shelley’s submission to their contest, later published anonymously in 1818.
I just have to chime in, as I also am so blown away by this book. It was so much more than I expected and gave me a an awful lot to think about, while simultaneously having a story which has so beautiful settings and keeps the readers interested. I read it two and a half years ago and the effect of this book lingers on.