Sefer HaYashar: the anonymous medieval ethical book
The Sefer HaYashar (ספר הישר), “The Book of Righteousness,” was one of the most popular ethical books of the Middle Ages. It is an anonymous work, probably written in the 13th century.
Quick facts
| Title | Sefer HaYashar (“The Book of Righteousness”) |
| Author | Anonymous (see below) |
| Composition | Around 1300, medieval Spain (according to Sefaria) |
| First printings | Istanbul, 1515 and 1520 (according to Sefaria) |
| Genre | Medieval Jewish ethics |
The question of authorship
The book was frequently attributed to Rabbeinu Tam, the Tosafist, who wrote a book with a similar name. Some manuscripts attribute it to Zerachiah ha-Yevani, but there is no evidence for this. Others have suggested Rabbeinu Yonah of Gerona, but his ideas are contradicted by the Sefer HaYashar. It remains an anonymous work.
Style and content
According to Sefaria, the style and language conform to the philosophical-ethical writings of the period, and the author makes use of Aristotelian terms and concepts. It also includes some beliefs that hint at possible kabbalistic tendencies, and its substance is similar to ideas found among the Chasidei Ashkenaz (see Sefer Chasidim).
Frequently asked questions
Who wrote the Sefer HaYashar?
Unknown: it is anonymous. It has been attributed to Rabbeinu Tam and to Zerachiah ha-Yevani, without evidence.
Is it the same as the biblical “Book of Jasher”?
This article deals with the medieval ethical book; we have not compared the two works.
Sources
- Sefer HaYashar, entry on Sefaria (description, dates and first printings)