Georgi Valentinovich Plekhanov was a Russian revolutionary, philosopher and Marxist theoretician. He was a founder of the social-democratic movement in Russia and was one of the first Russians to identify himself as Marxist. Facing political persecution, Plekhanov emigrated to Switzerland in 1880, where he continued in his political activity attempting to overthrow the Tsarist regime in Russia. Plekhanov is known as the "father of Russian Marxism".

In Marxism, a theoretician is an individual who observes and writes about the condition or dynamics of society, history, or economics, making use of the main principles of Marxian socialism in the analysis.