Political figure. In 1897 he graduated from the Jewish Teachers' Institute in Vilno. In 1898 he joined BUND. During the first decade of the 20th century he was active on the BUND Central Committee and edited various party publications. From 1917 to 1919, as chairman of the BUND Central Committee, he was an opponent of the Bolsheviks. In 1920 he was one of those who instigated a split in BUND, and a founder of KOMBUND. From 1921 he was a member of the Communist Party. During the 1920s he was chairman of the Belorussian SNKh (National Economic Council) and deputy chairman of the Belorussian Council of People's Commissars. He was one of the leaders of KOMZET, and a supporter of the "Crimea project". Later he worked in various Soviet economic organisations. He was arrested in 1938. According to the official version of events, he died while undergoing interrogation; the unofficial view was that he committed suicide.