The Book of Jasher is the English name of a work known in original Hebrew as Sefer haYashar, (ספר הישר; transliterated Sēper haiYāšār). It is the best-known of several "Lost books of the Old Testament", books which are referenced in the Hebrew Bible of which no copies are known to exist. The original Hebrew translates the Book of Jasher as the "Book of the Upright".
