Question:
Am I correct if I say that Jasher, refers not to a specific individual but means Upright in Hebrew, thus “The Book of the Upright Man” and the original writer of this book is unknown?
Answer:
Hello,
The technical translation of ‘yashar” means straight, not upright, therefore the translation of the book would be “The book of the Just”. There is confusion as to who the author was, many say that it was written by Rabbeinu Tam, a grandson of Rashi and one of the authors of Tosefos. There are however other opinions, one opinion is that it is from rabbeinu Zerachia of Greece (Shem Hagedolim), and others say that it is from the author of Sefer Hameor.
Best wishes
