The Voynich manuscript is an illustrated codex, hand-written in an unknown script referred to as Voynichese. The vellum on which it is written has been carbon-dated to the early 15th century (1404–1438). Stylistic analysis has indicated the manuscript may have been composed in Italy during the Italian Renaissance. The origins, authorship, and purpose of the manuscript are still debated, but currently scholars lack the translation(s) and context needed to both properly entertain or eliminate any of the possibilities. Hypotheses range from a script for a natural language or constructed language, an unread code, cypher, or other form of cryptography, or perhaps a hoax, reference work (i.e. folkloric index or compendium), glossolalia or work of fiction (e.g. science fantasy or mythopoeia, metafiction, speculative fiction).

A complete illuminated manuscript in high resolution full-page color plates. The Voynich manuscript is a richly illustrated codex hand-written in an undeciphered script. While the manuscript's origins are unknown it has been carbon-dated to the early 15th century and is most likely from Northern Italy or Central Europe. Its illustrations suggest that it is some form of pharmacopoeia or scientific treatise and it is divided by convention into six sections: herbal, astronomical, biological, cosmological, pharmaceutical and recipes. Wide ranging hypotheses on the nature of the script have been put forward - from it being a complex cipher system or unknown natural language to a sophisticated hoax or pure gibberish - and decoding it remains a popular challenge in cryptography. The manuscript is named after Wilfrid Voynich, a Polish book dealer who purchased it in 1912. It is currently held by the Beinecke Rare Book and Manuscript Library, Yale University.