The Liber Linteus Zagrabiensis (also rarely known as Liber Agramensis) (Latin for Linen Book of Zagreb or Book of Agram) is the longest Etruscan text and the only extant linen book. It remains mostly untranslated because of the lack of knowledge about the Etruscan language, though the few words which can be understood indicate that the text is most likely a ritual calendar.
The fabric of the book was preserved when it was used for mummy wrappings in Ptolemaic Egypt. The mummy and the manuscript are now kept in a refrigerated room at the Archaeological Museum in Zagreb, Croatia .
More information, including a bibliography, on the Wikipedia page