Easton's Bible Dictionary: M. G. Easton, M.A., D.D.
Upright. "The Book of Jasher," rendered in the LXX. "the Book of the Upright One," by the Vulgate "the Book of Just Ones," was probably a kind of national sacred song-book, a collection of songs in praise of the heroes of Israel, a "book of golden deeds," a national anthology. We have only two specimens from the book,