Machatzis HaShekel

Rabbi Shmuel ben Nathan ha-Levi—commonly called Kelin or Kolin after his Bohemian birthplace—was a halakhist of the Acharonic period, born around 1720 in Kolín, Bohemia. He received his Talmudic training there and, after marrying, settled in Boskovice (Boskowitz) in Moravia, where for close to six decades he conducted a yeshiva that drew many students; he died there in 1806. He is remembered above all for the work that became his byname, the Machatzis HaShekel, a super-commentary on the Magen Avraham—Avraham Gombiner's densely written gloss on the Orach Chayim section of the Shulchan Aruch, the principal code of Jewish law. Because it opens up that difficult layer, it was drawn into the standard printed editions of the code. He also wrote a companion commentary on the Shach to Yoreh Deah, along with Talmudic novellae and sermons.