Historian, publicist, public figure. While still a gymnasium student he came under the influence of social-democratic ideas through his elder sister. In 1908 he joined the BUND and in 1909 was collaborating with ORT. After the 1917 October Revolution he was active in the Menshevik faction and the right wing of the BUND; in 1922 he was arrested and exiled. He settled in Berlin and worked in the BUND archive, and published articles in emigrant newspapers and journals. He resumed co-operation with ORT, participating in the preparation of its publications. From 1926 to 1931 he was the General Secretary of the Central Executive of the World ORT Union. In 1930 he wrote his historical essay ‘Genesis of ORT. Pages from the history of the Russian Jewish intelligentsia’ (the manuscript is in the World ORT Archive, London, RG 1–4-12-2, which was published in English in a collection of articles entitled ‘80 Years of ORT. Historical Materials, Documents and Reports’. Geneva, 1960, pp. 33–54). From 1940 he lived in New York and worked on the newspaper Novoe russkoe slovo (New Russian Word). He  rote a number of historical and other works in Yiddish and Russian, including ‘The Jewish Problem in Soviet Russia’ (1944) and ‘Anti-Semitism in Soviet Russia’ (1953), as well as two collections of poems in Russian (1916 and 1923).