Vladimir Lenin
The speaker, and a Russian politician whose radical take on Marxism got him elected to the top following the Russian Revolution, which he helped to start.
Marx and Engels
Much of the preliminary discussion in the pamphlet deals openly with the writings of the founders of the communist philosophy, Karl Marx and Friedrich Engels. These two were thinkers and writers who worked together on the Communist Manifesto forming the political parties that we know as communism and socialism. Lenin was a purist and he treats the socialists as heretics in the cause of communism.
The Bourgeuoisie
The elite class, formed from successful businessmen, the upper middle class whose monetary value allows them to have their interests represented by the government.
The Proletariat
The common man, the worker. As individuals, they are typically lower income, and as a class, they're treated as a slave class to the interests of the bourgeoisie.