LEINER, GERSHON ḤANOKH (Henikh) BEN JACOB (1839–1891), ḥasidic rebbe. Leiner was born in Izbica, Poland, and studied with his grandfather R. Mordecai Joseph, the first rebbe of the Izbica-Radzyn dynasty, until the latter's death in 1854. He stayed with his father R. Jacob, the second rebbe, and moved with him to Radzyn, where he lived until his death, after which Leiner became the third rebbe (1878).
In contrast to his predecessors, R. Gershon Ḥanokh was a prolific writer whose works cover diverse fields and genres. He had a bold, unconventional personality and did not hesitate to initiate controversial innovations that put him in the eye of the storm. He documented the homilies of his grandfather (Meiha-Shilo'aḥ) and father (Bet Ya'akov), establishing the foundation of the Izbica-Radzyn dynasty's writings. Utilizing his outstanding talmudic erudition he composed Sidrei Taharot, a Gemara-style work on the tractates of Kelim (1873) and Oholot (1903) in Seder Taharot, for which there is no Babylonian Talmud. This work includes interpretation in the style of Rashi and Tosafot. In "Ha-Hakdamah ve-ha-Petiḥah" (introduction to Bet Ya'akov, 1890) he gives an historiographic account of the transmission and development of Torah, mainly Kabbalah, to his time. He made it a point to show that Maimonides was part of the kabbalistic tradition. He addressed the central theme in his grandfather's homilies: God's will as guiding all human deeds, including sins, in a kabbalistic sense. After traveling to the Naples aquarium he wrote a book called Sefunei Temunei Ḥol (1886), where he claimed that he had found the special ḥillazon (snail) and the way to produce *tekhelet (blue dye) from it for ẓiẓit. Radzyn and Breslau Ḥasidim dye their ẓiẓit accordingly to this day. Among his other prominent writings are Sod Yesharim and Orḥot Ḥayyim (1890), the latter being the best known. He was self-taught in medicine and wrote prescriptions that were honored in pharmacies.
A. Marcus, Ha-Ḥasidut (1980), 243–46; Ḥ.S. Leiner, Dor Yesharim (1909); S.Z. Shragai, Be-Netivei Ḥasidut Izbica-Radzyn (1972–74); S. Magid, Hasidism on the Margin (2003).