“Frankenstein; or, the modern prometheus” by Mary Wollstonecraft Shelley — a free Project Gutenberg ebook, available to read as an EPUB on BookMarket.
Subjects: Frankenstein's monster (Fictitious character) -- Fiction; Frankenstein, Victor (Fictitious character) -- Fiction; Gothic fiction; Horror tales; Monsters -- Fiction. Original source: https://www.gutenberg.org/ebooks/84.
This ebook is in the public domain in the United States; the Project Gutenberg eBook license applies to the original text.