Karl Radek (kärl rä´dyĬk), 1885–1939?, international Communist leader and journalist, b. Lviv (then in Austrian Poland); his original name was Sobelsohn. Radek participated in the 1905 revolution in Warsaw as a member of the Social Democratic party of Poland and Lithuania. He was a leading contributor (1906–17) to the social democratic press of central and Eastern Europe. During World War I he lived in Switzerland and was a staunch supporter of the Bolshevik proposal to turn the war into a revolutionary civil war. After the October Revolution in Russia (1917), Radek joined the Russian Communist party and participated in the Brest-Litovsk peace negotiations with Germany. In 1918 he was sent to Germany as a representative of the central committee of the Russian Communist party to help reorganize the German Communist movement. Jailed for a time in Berlin, he returned to Russia and became (1920) a leading official of the Comintern. The failure of the Comintern to effect a Communist takeover in Germany contributed to the decline of Radek's influence, and in 1924 he lost his seat on the central committee of the Communist party. Expelled from the party (1927), he recanted and was readmitted (1930). A brilliant writer for the government newspaper Izvestia, Radek was also coauthor of the 1936 Stalin constitution. In the party purges of the 1930s he was accused of treason; he confessed (as did his codefendants) in the so-called Trial of the Seventeen (1937). He is believed to have died in a prison camp.
See W. Lerner, Karl Radek (1970); J. Tuck, Engine of Mischief (1988).