Russian-German socialist who helped enable Lenin to reenter Russia in 1917 from exile in Switzerland, thus helping to ignite the Russian Revolution of (Russian Revolution of 1917) October 1917.

Helphand, the son of Jewish parents, grew up in Odessa, on the Black Sea. He was attracted to revolutionary Socialism at an early age and became a Marxist during his prolonged residence in Germany (from 1891), where he eked out a living as an itinerant left-wing journalist. He met Lenin and Trotsky and other exiled revolutionaries and returned to Russia to participate in the Revolution of 1905. Arrested by the Russian police and sentenced to Siberia in 1906, he escaped to Germany and never returned to his native country.

With the onset of World War I, Helphand was able to obtain subsidies from the German government in exchange for his advice on ways to subvert Russia's tsarist regime. He also convinced the German government to provide him with large sums to funnel to the Bolsheviks (Bolshevik), though it is unlikely that this service had much impact. Although Helphand helped negotiate with German authorities Lenin's (Lenin, Vladimir Ilich) passage in the notorious “sealed train” across Germany on the way to Russia in April 1917, Lenin refused to allow the disreputable Helphand to return to Russia after the October Revolution of 1917.

A man of dissolute character, Helphand grew immensely rich as a result of his trading and publishing ventures during World War I. A bold thinker in many respects, he was viewed as a brilliant but unscrupulous maverick by many of his fellow revolutionaries throughout his career.