The Book of Jasher (also, Jashar) or the Book of the Upright or the Book of the Just Man (Hebrew: סֵפֶר הַיׇּשׇׁר; transliteration: sēfer hayyāsār) is an unknown book mentioned in the Hebrew Bible. The translation "Book of the Just Man" is the traditional Greek and Latin translation, while the transliterated form "Jasher" is found in the King James Bible, 1611.