R. Jacob ben Aaron of Karlin (Baruchin; d. 1844) was a Lithuanian rabbi and author. He was a grandson of R. Baruch ben Jacob of Shklov, and a pupil of R. Hayyim of Volozhin. R. Jacob was first rabbi of Gorodok and later of Karlin, where he served for 30 years, until his death. In addition to Mishkenot Ya’akov he wrote Kehillat Ya’akov (1847), novellae on a number of tractates of the orders Zera'im and Mo'ed. His halakhic works were highly esteemed by yeshivah students, by whom they were much used. R. Jacob's brother R. Isaac, after devoting himself to business, succeeded him in the rabbinate of Karlin. He too, also achieved an outstanding rabbinical reputation, and was the author of Keren Orah (2 parts, 1852–57), on a number of tractates of the Talmud. Both brothers were noted for their struggle against the kidnapping of children for impressment into the Russian army.