In the Beinecke Rare Book and Manuscript Library, part of Yale University, there is a book that nobody can read. Called the Voynich Manuscript, after the book dealer Wilifrid Voynich, who acquired the book in 1912, has proven to be an unsolvable puzzle to scholars, cryptographers, and bibliophiles.
C14 dating on the manuscript’s pages has dated the book to sometime in the 15th century. The text is written in an alphabet that matches no known language, and if it’s a code, then it’s one that has stumped codebreakers and cryptographers for the last 100 years. The book appears to be part pharmacopeia, with illustrations of plants and herbs, part alchemy text, and part cosmological treatise. If it is, as some believe, a hoax, it is an incredibly complex one.