BEN-ADIR (pen name of Abraham Rosin ; 1878–1942), writer and Jewish socialist leader, born in Krucha, Belorussia. He received a traditional Jewish education from his grandfather Jacob Aaronson and his uncle Solomon Aaronson. At the age of 16 he went to Odessa to sit for the university examinations as an external student, and then moved to Minsk. In 1896–97 he became influenced by A. *Liessin who advocated a Jewish national brand of socialism. After the First Zionist Congress in 1897, Ben-Adir published an article advocating political Zionism in opposition to the ideology of *Aḥad Ha-Am. In 1901 he moved to Paris where he studied at the Free Russian University, and later returned to Russia. After the *Kishinev pogrom of 1903 Ben-Adir published a call for the formation of a Jewish party which would combine the aims of revolutionary socialism with national Jewish aspirations. Ben-Adir was one of the founders and ideologists of the *Vozrozhdeniye group, and of its successor of the Sejmists (*Jewish Socialist Workers' Party) whose program included Jewish national-political autonomy while envisaging *Territorialism as a remoter aim. He edited its organs Serp (Russian) and Folksshtime (Yiddish). After the February 1917 Revolution, Ben-Adir became a leader of the *United Jewish Socialist Workers' Party. Also in 1917 he published Kehile Fragen, a pamphlet envisaging the kehillah as an instrument of national Jewish *autonomy. Ben-Adir withdrew from the united party in 1919 when the communist trend predominated, and in 1921 left Russia for Berlin. His In Khaos fun Lebn un Denken ("Whirlwind of Life and Thought"), a collection of essays on socialist problems, in particular an argument against communism, was published in 1925. Ben-Adir stayed in Ereẓ Israel between 1925 and 1927 but returned to Berlin, leaving for Paris in 1933. After the French defeat by the Nazis in 1940 he went to the United States. In Paris and New York he coedited the Algemeyne Entsiklopedye ("General Encyclopedia" in Yiddish) to which he also contributed.
lnyl, 1 (1956), 336–9; Rubin, in: Asufot, 1 (1945), 21–25.