Book of Jasher (biblical book)

The Book of Jasher (also spelled Jashar; Hebrew: סֵפֶר הַיׇּשׇׁר Sēfer haYyāšār), which means the Book of the Upright or the Book of the Just Man, is a lost book mentioned in the Hebrew Bible, often interpreted as a lost non-canonical book. Numerous forgeries purporting to be rediscovered copies of this lost book have been written. A different interpretation identifies it as a reference to the Pentateuch, specifically the Book of Genesis, an interpretation which is notably favored by the Jewish scholar Rashi in his commentary on the Hebrew Bible (see below his commentary on Joshua).

The title “Book of the Just Man” is the traditional Greek and Latin translation, while the transliterated form "Jasher" is found in the Apocrypha section of the 1611 King James Bible.