Rabbi Ẓebi Hirsch Kaidanover (c. 1650[1] – 1712), a native of Wilna;[2] was the author of Kav ha-Yashar (Hebrew: קב הישר).
[2] In Frankfurt he recovered from the trials through which he had passed and found leisure to engage in literary pursuits.
Besides publishing his father's works, which he in part accompanied with notes (as in the case of "Birkat Shemuel"), he wrote a book on morals entitled "Kav ha-Yashar," being a combination of ethics and asceticism.
Rabbi Zebi Hirsch also made a Yiddish translation of his work which has often been published together with the Hebrew text (as ed.
A similar book on morals was written by his son-in-law, Rabbi Manoah Hendel Kirchhahn, under the title "Simḥat ha-Nefesh" (שמחת הנפש).