R. Mordechai Joseph Eleazar Leiner (1867-1929) son of R. Gershon Hanokh b. Jacob Leiner (1839–1891), talmudic scholar and hasidic rabbi. Leiner, popularly known as the "Radzyner Rebbe," was a prolific writer in several areas, his works including novellae on the Babylonian Talmud, Binyan Yerushalayim, on the Jerusalem Talmud, and commentaries on the Pentateuch, Maimonides'Guide of the Perplexed and the Zohar. By gathering together scattered references from the vast talmudic literature, he compiled Sidrei Tohorot, a gemara to the order Tohorot (for most of which no original gemara exists), even adding commentaries on the pattern of Rashi and Tosafot. He completed this enormous achievement before his 30th year. The work followed the pattern of the standard tractates of the Talmud so closely that it aroused some opposition, on the grounds that future generations might regard the work as actually belonging to the talmudic period. Much of his later work on Sidre Tohorot has remained in manuscript. Another of his innovations also encountered considerable opposition. He claimed that the cattle fish was the biblical hillazon, from which the blue dye of tekhelet referred to in Num. 15:38 was obtained, and he revived the practice, which had fallen into disuse for centuries, of having a double thread of the zizit of that blue dye. The innovation was adopted mainly by his Hasidim.