Public figure, economist, agricultural specialist, publicist. Studied agronomy in Poland. From 1902 to 1908 he was head of the agricultural department of EKO in Russia. From 1907 he taught at the Petersburg Agricultural Institute. He was one of the leaders of the Jewish People's Party (Volkspartei). In the second decade of the 20th century he took part in the work of the Petersburg ORT; from 1915 to 1917 he was editor of a magazine entitled "The Bulletin of Jewish Labour". In 1922 he was exiled from the USSR and lived subsequently in Germany and France. He joined the board of the World ORT Union, and was one of the leaders of OZE. From 1936 he was a professor at the Hebrew University of Jerusalem.